Could Discovery of Mammoth Blood Lead to Revival of Species?

Could Discovery of Mammoth Blood Lead to Revival of Species?

Researchers have uncovered the carcass of a female mammoth in Russia which may include 10,000-year-old mammoth blood , paving the way for the potential to revive a remarkable species from our ancient past.

Unlike other mammoth discoveries, the recent finding in Russia’s Novosibirsk Islands was incredibly well-preserved by the northern deep freeze and has large amounts of soft tissue still intact. But of particular interest, is the fact that scientists discovered a peculiar liquid around the carcass which they believe to be blood still containing viable cells.

"Whatever we want to call the red material, it would be fantastic if it contained intact cells," says Ross Macphee, an Ice Age mammal expert at the American Museum of Natural History. "I await secure identification on this point."

Others believe the hope of finding viable cells may be a long shot but experts wait in anticipation as the potential implications of such a discovery would be huge. Imagine the possibility of future generations taking their children to a wildlife park to see a living, breathing mammoth that once abounded the earth 10,000 years ago along with our ancient ancestors.

Despite the remarkable finding, scientists are still a long way off cloning a mammoth and finding a way for a modern Asian elephant – the closest living relative to the mammoth – to carry a baby mammoth.

Such a possibility does, however, raise ethical issues. Is it right for mankind to bring back species of the past into a new foreign world? And if so, where do we draw the line? Would it lead to the revival of Neanderthals and other ancestors of the human? Some have argued that instead of focusing time and resources on bringing back ancient species we should instead be concentrating on preventing the loss of thousands of species around the planet that currently face extinction.


    Scientists discover world's 'best-preserved woolly mammoth trunk'

    A Siberian-led international team finds 10,000 year old red 'meat' on female remains excavated from permafrost in Sakha Republic.

    'It is the best preserved adult mammoth trunk ever found. Its red meat, skin and hairs are in good condition. It looks like a freshly killed animal meat'. Pictured left to right are Sergey Fedorov ( Mammoth Museum, North Eastern Federal University/NEFU), Teodor Obada (Academy of Science, Moldova), Alexei Tikhonov (Zoological Museum, Russian Academy of Science, St. Petersburg), Daniel Fisher (University of Michigan), Gavril Novgorodov ( Mammoth Museum, NEFU), Konstantine ( Mammoth Museum, NEFU), and Semyon Grigoriev ( Mammoth Museum, NEFU). Picture: Victor Makarov

    The recent discovery is causing major excitement among world teams seeking to complete the genome sequencing of the extinct creature, heralding attempts to bring the woolly mammoth back to life, The Siberian Times can exclusively reveal. The trunk was examined by Russian, American, South Korean and Moldovan scientists on a recent expedition to the north of Sakha - also known as Yakutia.

    'We found a perfectly preserved trunk,' said Semyon Grigoriev, head of the Mammoth Museum in Yakutsk, part of the Institute of Applied Ecology of the North at the North Eastern Federal University.

    'It is the best preserved adult mammoth trunk ever found. Its red meat, skin and hairs are in good condition. It looks like a freshly killed animal meat.'

    The trunk has been brought to Yakutsk, the regional capital, as scientists from South Korea, the US, Canada, Holland and elsewhere seek permission from the Russian authorities to export samples for detailed DNA analysis.

    'We have many partners now, and they all want samples,' said Grigoriev.

    The trunk has been brought to Yakutsk, the regional capital, as scientists from South Korea, the US, Canada, Holland and elsewhere seek permission from the Russian authorities to export samples for detailed DNA analysis. Picture: Semyon Grigoriev

    The carcass was originally found in May 2013 on Malolyakhovskiy island and transported in a frozen condition to remote Kazachiy, in the north of the Sakha Republic, where it was examined by the international team.

    Earlier this year, the same 10,000 year old year old mammoth remains hit the headlines around the world after a 'blood sample' preserved in the permafrost was extracted for analysis. This blood research is still going on, but the existence of the trunk only came to light on the recent August expedition when Western documentary-makers joined scientists.

    The expert said that tests in Russia have so far produced 'no clear results' and the there are plans to send samples to the University of Manitoba, Aarhus University, and Lund University, as well as to South Korea for further research.

    'We took it out of the icehouse and it just laid outdoors,' said Dr Grigoriev, explaining the moment when the experts had the chance to scrutinise the mammoth remains for the first time.

    'For three days, it didn't fully melt, but we didn't need this. It was important to save some part of the biological material frozen inside. The trunk was detached from the beginning. It melted faster.

    'We thawed it for one day, but not completely, of course. We cleaned it and froze it again. The trunk is the most valuable part of the remains at the moment.

    'We understood this when we saw the red soft tissues inside. It looked like the meat of a freshly killed animal. It is red and we can see the muscle.

    'It smells like not very fresh meat. Sometimes the corpse remains of ancient animals are so decomposed that the smell is unbearable. It all depends on the preservation, here it was better and the smell was not so strong.'

    'Of course, we hope to find so called 'living cell' in the samples. That means we can get the least damaged DNA and first of all - nuclear DNA'. Picture: Semyon Grigoriev

    Earlier there were suspicions that marks on the beast indicated it had been killed by man. Subject to further tests, the current theory is that the woolly mammoth died perhaps from drowning after becoming mired in an ice hole or frozen swamp, or possibly from illness.

    Grigoriev described the 'excitement, the feeling of discovery, when every minute, every hour, brings something new' as the scientists examined the frozen remains.

    He explained: 'Everybody is talking about about cloning, but we should understand that it is a very complicated task. Of course, we hope to find so called 'living cell' in the samples. That means we can get the least damaged DNA and first of all - nuclear DNA. But this is only a midway point.

    'The next question is how to use an elephant in the cloning process. The evolutionary path of the mammoth and the elephant diverged a long time ago. So even if we could get a 'living cell' we need to have a special method of cloning. The Koreans are working on getting the clones from different species, but, you see, it is not so fast.

    'If we do not get 'living cell', we will have a longer route. Then we should create artificial DNA. It could take 50 or 60 years.

    'Apart from cloning, these samples will give us an opportunity to completely decode the DNA of the mammoth, and we will be able to decipher the nuclear DNA, which stores a lot of information.

    'So we have a unique opportunity to understand how the mammoth's blood system, worked, its muscles and the trunk. Of course, we are engaged primarily in fundamental science. It is important to us to learn all possible details about mammoth. Maybe our findings will be used by applied science, but now it is early to think of it. And I repeat once again that cloning - despite our discovery, it is a very distant prospect, involving years and decades of work'.

    'Grigoriev described the 'excitement, the feeling of discovery, when every minute, every hour, brings something new' as the scientists examined the frozen remains'. Picture: Semyon Grigoriev

    The significance of the recent find was underscored by US academic Daniel Fisher, Professor, Ecology and Evolutionary Biology as well as Earth and Environmental Sciences at the University of Michigan, where he is also Curator and Director at the Museum of Paleontology.

    'The Malolyakhovskiy mammoth is quite variable in its degree of preservation, with some parts in excellent condition, as good, or in some cases slightly better, than anything we have seen before, and other parts that are not especially well preserved at all,' he told The Siberian Times.

    'This is consistent with Semyon Grigoriev's initial report. Parts of the body that are very well preserved include the oral region, the front of the chest, and the lower portions of the front legs.'

    Asked about Grigoriev's claim that the mammoth's trunk is the best preserved in the history of paleontology, he said: 'Yes, I would agree with this, with the additional qualification that we have seen an excellent trunk of a juvenile on Lyuba, but this is the best preserved trunk of an adult mammoth.'

    Lyuba was found in 2007 on the Yamal Peninsula, also in Siberia.

    The new specimen 'will provide a better idea of how the trunk anatomy of woolly mammoth differs from that of elephants,' Professor Fisher said.

    'We have a general idea of this now, but this specimen will give a more detailed understanding. How much we will be able to find out about how the trunk works is unknown until we get further into the investigation. What we learn may also depend on finding collaborators knowledgeable about elephant anatomy.'

    More generally the latest carcass 'will contribute new insights that will be relevant for the study of mammoths everywhere, not just in Russia,' said the American professor. He is confident that scientists can unlock secrets about this mammoth's life from studying its well-preserved remains.

    'I expect to return to Yakutsk early next year to participate in additional work on the specimen with my Yakutian colleagues.'

    The female mammoth was believed to have died at an age of 50 or 60.

    Researchers are preparing for the opening of a laboratory to be involved in the separation of 'live' cells from ancient remains. Pictures: Semyon Grigoriev

    'I hope to learn more about this animal's life from studying its tusks, and if that can be done, we might use one or both tusks to develop new methods of interpreting tusks,' he said. 'Since this is a moderately old female, her tusk should hold a record of her calving history, but we will have to study it from different perspectives to be sure we can really get such information.'

    He believes additional research is required on liquid resembling blood that was gathered from the remains as it was removed from its ice-clad grave in the Novosibirsk - or New Siberian - Islands in May.

    'I saw some samples that were said to 'look like' the 'blood' samples, but I did not see the actual samples that first appeared to resemble blood. I suspect this is mainly something else, but I did not have access to the necessary equipment or time to do a definitive analysis of this material on site.'

    'I would say additional investigation is needed', Professor Fisher said.

    The scientists were monitored by film crews from the US and UK - CB Films and Renegade Pictures - as they went about their work, with documentaries expected on the National Geographic Channel and Britain's Channel 4 next year. So far only certain samples, including the trunk, have been flown to Yakutsk.

    'Now it is in Yakutsk and we can thoroughly examine muscle tissue, blood vessels,' said Grigoriev. 'The blood system of the mammoth is different from that of the elephant. They lived in a cold climate, and the blood system was more extensive. It was a complex of adaptation and we should examine it thoroughly.'

    Left to right, Semyon Grigoriev ( Mammoth Museum, NEFU) and Alexei Tikhonov (Zoological Museum, Russian Academy of Science, St. Petersburg) during Yana 2012 expedition in Yakutia. Picture: Semyon Grigoriev

    This week, a fund raising initiative has been started to fund joint research by the North-Eastern Federal University in Yakutsk and South Korean laboratory SOAAM 'Revival of the Mammoth'.

    Currently researchers are preparing for the opening of a laboratory to be involved in the separation of 'live' cells from ancient remains.

    'We plan to start the laboratory by the end of the year. Joint expeditions to find the remains of mammoths and other ancient remains are completed, and now scientists are beginning to analyse the materials.

    'Some samples will be taken for study in Korea. In the laboratory, which we plan to open will be the held the first stage of the research - the allocation of those 'live' cells, on which depends the future of cloning the mammoth,' said Grigoriev.

    The laboratory will study not only the remains of a mammoth, but other relic animals.


    Are Scientists on the Verge of Resurrecting the Woolly Mammoth?

    Every summer, groups of hunters head to the remote, uninhabited New Siberian islands in search of the elusive “white gold”𠅊 perfectly formed tusk of a woolly mammoth—hidden in the thawing Arctic permafrost.

    They are not only exploring the furthest reaches of the Arctic Ocean, but traveling back in time, carrying out a primordial quest for the tusks of the massive beasts that roamed the forbidding landscape in droves before going extinct 10,000 years ago.

    Of course, there’s always the chance the hunters may stumble not just on a tusk or two, but on an entire set of mammoth remains, including fur, flesh and even oozing blood.

    An illustration of a family of Woolly Mammoths.

    That’s what happened in 2013, when a team from Yakutsk, Russia, uncovered the almost-complete carcass of a young female mammoth buried in the permafrost on the New Siberian Islands. Not only were three legs, a majority of the body, part of the head and the trunk still relatively well preserved, but when the researchers began efforts to dislodge the animal’s remains, they noticed dark, sticky blood oozing from the carcass.

    Carbon dating revealed that Buttercup, as she was dubbed, lived some 40,000 years ago. From her remains, including a vial of blood drained from her carcass, scientists hoped to extract living mammoth cells that will yield intact DNA—the missing link in modern scientists’ long-running quest to bring this ancient behemoth back from the dead.

    In the new documentary film Genesis 2.0, Swiss documentarian Christian Frei and his co-director, Siberian filmmaker Maxim Arbugaev, follow the intrepid mammoth tusk hunters in the New Siberian Islands, as well as various scientists in the United States, Russia, South Korea and China who are working to bring the mammoth back to life in one form or another.

    Traditional Chinese carvers make elaborate sculptures out of mammoth ivory, and first-class mammoth tusks can net the hunters tens of thousands of dollars on the international market, especially since China banned the import and sale of elephant ivory in 2016. Russia exported 72 metric tons of mammoth ivory in 2017, with more than 80 percent of it going to China.

    For the Siberian mammoth hunters, finding a top-notch tusk to sell is the goal, of course𠅊 lot of what they find is in poor condition𠅋ut it’s also a mixed blessing. In local culture, which has long considered the woolly mammoth a sacred beast, it is considered bad luck to touch mammoth remains, let alone remove them from the earth. 

    “The tusk hunters have very mixed feelings when they are lucky,” Frei says. “It feeds their families, and they&aposre desperately hoping for this sheer luck. But when they do find the nice tusks, then they have these mixed feelings of being really afraid.”

    Whatever the market value of a preserved ancient tusk is, it’s nothing compared to the scientific community’s high-stakes quest to resurrect the woolly mammoth, Jurassic Park-style. Since 2015, a team led by the renowned molecular engineer and geneticist George Church of Harvard University has been working to produce a mammoth-elephant hybrid, rather than a clone. They plan to do this through “synthetic biology,” or splicing the genes of a woolly mammoth with those of an Asian elephant, its closest living relative, which shares 99 percent of its DNA.

    George church, genetics professor at Harvard (left), and South Korean Scientist Hwang Woo-suk.

    Wendy Maeda/The Boston Globe/Getty Images & Jung Yeon-Je/AFP/Getty Images

    Then, of course, there’s the work going on at South Korea’s Sooam Biotech Research Foundation, headed up by the controversial veterinarian and cloning expert Hwang Woo-suk. Scientists there have already mastered the process of cloning your beloved pet dog𠅏or a cool $100,000. Barbra Streisand is among the celebrities known to have had her dog cloned, and Hwang has even donated some experimental puppies for use as Russian police dogs.

    But despite dedicated effort, scientists have not yet managed to clone a woolly mammoth, although they keep trying. In addition to the Sooam scientists, researchers in Russia are still searching for living mammoth cells within the remains of Buttercup and other recovered mammoth carcasses, but the nature of DNA itself poses a serious challenge to their quest.

    “The mammoth is an iconic animal. I mean, who wouldn&apost want to see it?” Frei says of the cloning efforts. Yet he spoke with specialists who told him “postmortem DNA is decaying within hours sometimes. It&aposs very delicate.”

    Those looking to see the woolly mammoth’s return may want to pin their hopes to synthetic biology, rather than cloning: Within the next decade, George Church and his team expect to create the first mammoth-elephant hybrid. Their efforts aim not only to protect the endangered Asian elephant, but to combat global warming. By grazing on the Arctic tundra, the animals would expose the earth underneath to the cold air, keeping it frozen longer.

    While turning back the climate change clock is a worthy goal, watching Genesis 2.0 helps make clear that if scientists are able to resurrect the long-extinct woolly mammoth, they aren’t likely to stop with just one prehistoric beast. 

    “The resurrection of the woolly mammoth is the first manifestation of something much bigger,” Frei says. “You can&apost say where this is all going, but it will be definitely the next big technological evolution.”  


    Scientists Extracted Liquid Blood From 42,000-Year-Old Foal Found in Siberian Permafrost

    Last August, a group of mammoth tusk hunters unearthed the nearly intact remains of a 42,000-year-old foal during an expedition to Siberia’s Batagaika crater. Preserved by the region’s permafrost, or permanently frozen ground, the young horse showed no signs of external damage, instead retaining its skin, tail and hooves, as well as the hair on its legs, head and other body parts.

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    Now, the Siberian Times reports, researchers from Russia’s North-Eastern Federal University and the South Korean Sooam Biotech Research Foundation have extracted liquid blood and urine from the specimen, paving the way for further analysis aimed at cloning the long-dead horse and resurrecting the extinct Lenskaya lineage to which it belongs.

    To clone the animal, scientists would need to extract viable cells from the blood samples and grow them in the lab. This task is easier said than done: Over the past month, the team has made more than 20 attempts to grow cells out of the foal’s tissue, but all have failed, according to a separate Siberian Times article. Still, lead Russian researcher Lena Grigoryeva says, those involved remain “positive about the outcome.”

    The fact that the horse still has hair makes it one of the most well-preserved Ice Age animals ever found, Grigoryev tells CNN's Gianluca Mezzofiore, adding, “Now we can say what color was the wool of the extinct horses of the Pleistocene era.”

    In life, the foal boasted a bay-colored body and a black tail and mane. Aged just one to two weeks old at the time of his death, the young Lenskaya, or Lena horse, met the same untimely demise as many similarly intact animals trapped in permafrost for millennia.

    The scientists extracted liquid blood samples from the 42,000-year-old animal's heart vessels (Semyon Grigoryev/North-Eastern Federal University)

    The foal likely drowned in a “ natural trap ” of sorts—namely, mud that later froze into permafrost, Semyon Grigoryev of Yakutia’s Mammoth Museum told Russian news agency TASS, as reported by the Siberian Times . “A lot of mud and silt which the foal gulped during the last seconds of [the foal’s] life were found inside its gastrointestinal tract,” Grigoryev says .

    This is only the second time researchers have extracted liquid blood from the remains of prehistoric creatures. In 2013, a group of Russian scientists accomplished the same feat using the body of a 15,000-year-old female woolly mammoth discovered by Grigoryev and his colleagues in 2013, as George Dvorsky reports for Gizmodo. (It’s worth noting that the team studying the foal has also expressed hopes of cloning a woolly mammoth.) Significantly, the foal’s blood is a staggering 27,000 years older than this previous sample.

    The NEFU and South Korean scientists behind the new research are so confident of their success that they have already begun searching for a surrogate mare to carry the cloned Lena horse and, in the words of the Siberian Times, fulfill “the historic role of giving birth to the comeback species.” It’s worth noting, however, that any acclaim is premature and, as Dvorsky writes, indicative of the “typical unbridled enthusiasm” seen in the Russian news outlet’s reports.

    Speaking with CNN's Mezzofiore, Grigoryev himself expressed doubts about the researcher's chances, explaining, “I think that even the unique preservation [of] blood is absolutely hopeless for cloning purposes since the main blood cells . do not have nuclei with DNA.”

    He continued, “We [are] trying to find intact cells in muscle tissue and internal organs that are also very well-preserved.”

    What the Siberian Times fails to address are the manifold “ethical and technological” questions raised by reviving long-gone species. Among other concerns, according to Dvorsky, scientists have cited the clone’s diminished quality of life, issues of genetic diversity and inbreeding, and the absence of an adequate Ice Age habitat.

    It remains to be seen whether the Russian-South Korean team can actually deliver on its ambitious goal. Still, if the purported July 2018 resurrection of two similarly aged 40,000-year-old roundworms “defrosted” after millennia in the Arctic permafrost is any indication, the revival of ancient animals is becoming an increasingly realistic possibility.


    De-Extinction: If We Could Revive a Species, Does It Mean We Should?

    Few creatures have ever existed that can match the sheer weirdness of Australia’s gastric brooding frog. As the name suggests, the amphibian had the strange ability to reproduce offspring in its stomach. The female would release a cloud of eggs, the male would fertilize them, and then the female swallowed the eggs whole. At that point, the female ceased making digestive acids and her stomach became, essentially, a womb. A few weeks would pass, and then the female would open her mouth and a batch of babies would issue forth. Think of it as the swampland version of Zeus birthing Athena out of his forehead: a beast that pukes its young into the world.

    This wonderful oddity no longer exists. Biologists didn’t identify the frog until relatively recently—and then it almost immediately disappeared. The southern gastric brooding frog was described in 1973, discovered in a narrow range of streams on Australia’s east coast the last sighting occurred in 1979. Its cousin, the northern gastric brooding frog, wasn’t discovered until 1984 the last one was seen just a year later. One of the main culprits of the frogs’ demise was a pathogen called the chytrid fungus. As usual, humans accelerated the rush toward extinction. Much of the frogs’ habitat was destroyed by invasive weeds and feral pigs. The miraculous animal was gone as soon as we knew it.

    Now, in a new twist on miracle, scientists are on the verge of bringing the frog back.

    In March researchers with the Lazarus Project announced they had cloned gastric brooding frog embryos. Forty years ago, a biologist happened to throw a few specimens into a freezer before the species went extinct. Today’s researchers were able to obtain cell nuclei from the tissues collected in the 1970s. “Almost miraculously, we were able to extract viable DNA from the specimens,” one of the Lazarus Project scientists, Simon Clulow, wrote to me in an email. Using a technique called somatic cell nuclear transfer, the team injected the gastric brooding frogs’ DNA into inactivated egg nuclei from the great barred frog. Some of the eggs began to spontaneously divide. Although none of the embryos survived beyond a few days, tests confirmed that the dividing cells contained the genetic material from the extinct frog. “We are watching Lazarus arise from the dead, step by exciting step,” the team leader, Mike Archer of the University of New South Wales, said in announcing the news.

    What was sci-fi fantasy only a few decades ago is now well within the realm of the possible. Asked how close his team was to having a living, breathing gastric brooding frog, Clulow wrote: “We are confident this will only be a matter of a small number of years, perhaps less.”

    The Lazarus Project is part of an emerging field of science called “revival biology.” Advances in cloning, genetic sequencing, and synthetic biology—along with successes in more old-fashioned “back breeding”—have opened up the possibility of returning to the world species that are long gone. Scientists are busy trying to revive the passenger pigeon, the European auroch and the Pyrenean ibex. Proponents of de-extinction also dream of resuscitating the dodo, the Carolina parakeet, the Steller’s sea cow and the thylacine, a wolf-like marsupial known as the Tasmanian tiger that was hunted to extinction in the 1930s. If any of those creatures were ever to walk or swim again, it would be the realization of one of humans’ most ancient wishes: the power to bring life back from the dead.

    De-extinction champions say species revival offers humanity a chance for redemption. By recreating species that we drove into the great void of extinction, we could right a historical wrong. Just as important, de-extinction proponents argue, revival biology can provide a new spark to the global conservation movement. Imagine a flock of passenger pigeons in the sky: The sight alone would reinvigorate civilization’s apparently flagging sense of awe with nature. Call it re-wilding from a test tube.

    “I think de-extinction can enrich conservation efforts,” says Ryan Phelan, executive director of the Revive & Restore project at the Long Now Foundation. The group has dedicated itself to serving as a clearinghouse for information about de-extinction, and Phelan has become one of revival biology’s most impassioned promoters. “I think it takes the inspiring vision of de-extinction … to help move all of this forward. As controversial as all of it is, and possibly because it’s controversial, it’s going to help drive interest in [species loss], in a way that conservation by itself couldn’t do. Because at the end of the day, the species that we are talking about bringing back, they really are part of the continuum of life. And I think that’s the real power in what we are trying to do. We’re calling attention to the extinction threat.”

    Yet even those who support de-extinction acknowledge that many risks are involved. There are political and ethical concerns: Will the idea make us cavalier about extinction, leading us to wreck the planet even more recklessly, believing we can repair the damage? There are ecological worries: what if we end up bringing back the passenger pigeon and it becomes an avian version of kudzu? For some people, there is a visceral fear that de-extinction is just the virtuous version of synthetic biology’s darker side—the creation of “customized species” and “perfected humans.”

    Some eminent conservation biologists say the whole thing is a waste of time. “I’ve been trying to tell people, ‘I bloody well won’t talk about it,’” Stuart Pimm, a professor of conservation ecology at Duke University, told me in an interview he agreed to only reluctantly. “It’s not worth my time. It’s not worth yours. The idea that this is going to be much of a solution is fanciful at best.”

    The debate about de-extinction centers on a classic dilemma. Just because we can do something, does that mean we should? For environmentalists, the answer largely depends on whether you think de-extinction will advance conservation efforts, or undermine them.

    I promised myself I wouldn’t mention Jurassic Park— but, what the hell, Michael Crichton was onto something. The 1990 bestseller and subsequent Spielberg blockbuster might have been outlandish, but the science wasn’t all wrong. No, we won’t be able to bring back the dinosaurs. Scientists say reviving an extinct species will require relatively intact original DNA, and that will limit us to species that have disappeared during roughly the last 200,000 years. But if Jurassic Park remains a fantasy, a Pleistocene Park might be doable. Given enough time and money (and a good bit of laboratory luck), scientists could create a simulacrum of a wooly mammoth. Or a giant ground sloth. Or a Neanderthal. We won’t have to worry about velociraptors getting loose—just saber-toothed tigers.

    As in the fictional Jurassic Park , reviving a long lost species would involve sequencing the genome of an extinct animal and then splicing in genes from its closest living cousin through what’s called “allele replacement.” The most advanced efforts so far have focused on the passenger pigeon. In the nineteenth century, flocks of passenger pigeons darkened the skies of North America. Then habitat loss and market hunters’ shotguns whittled away at the birds’ numbers. The last known passenger pigeon—“Martha” she was dubbed—died at the Cincinnati Zoo in 1914.

    A 26-year-old genetic engineer and bird lover named Ben Novak is spearheading the effort to revive the passenger pigeon. Novak grew up in a conservation-minded family, and when he was a teenager he developed a fascination with the passenger pigeon, a bird very similar to the common rock pigeon, only graced with a longer tail and a handsome red breast. “I am a very, very passionate passenger pigeon enthusiast,” Novak told me. “There are people in the world who love pigeons. And within that group there are people who become life-long obsessives with the passenger pigeon. I fell into that group when I was very young.” Novak works in the lab of University of California-Santa Cruz researcher Beth Shapiro. Together, the two are steadily decoding the DNA of the passenger pigeon and its closest surviving kin, the band-tailed pigeon.

    Novak has been able to gather 65 tissue samples from preserved passenger pigeons and has also obtained some bone fragments dating back to the 1700s. He has completed genetic sequencing on a third of his samples he expects to have a “first draft” of the passenger pigeon’s genome by the end of this year. Meanwhile, Shapiro is assembling the genome of the band-tailed pigeon. Once completed, the band-tailed pigeon genome will be used, Shapiro says, “as a scaffold on which to map the DNA of the passenger pigeon.” Because of natural decay, the passenger pigeon DNA will be incomplete. Genes from the band-tailed will be needed to fill in holes. But some of the passenger pigeon’s traits—say, the distinctive red breast—may be lost altogether. To fill in those patches, the geneticists will have to synthesize new genes through a process of “inference and experimentation,” in Novak’s words. Organizing the band-tailed pigeon genes, the recovered passenger pigeon genes and the synthetic genes is very similar to “writing a paper from a whole lot of different sources,” Novak says. “Even if the first individual is not right, we will have a stepping stone to make it better.”

    How close can the researchers get to nature’s original? “I think we can probably get into the 80 or 90 percent range,” Novak says. Shapiro is more circumspect. “How close are we to having an exact passenger pigeon?” she emailed me. “Infinitely far away. A hybrid of some sort, with a less-than-random selection of genes that hopefully impact the behavior or phenotype of a band-tailed pigeon and make it act more like a passenger pigeon.”

    In theory, this process could revive many other species that haven’t roamed the planet in centuries, or even millennia. Genes from a zebra could be used to splice together a quagga, a half zebra-half horse creature that once inhabited southern Africa. Take the genome of the Asian elephant, combine it with ancient DNA, and a wooly mammoth (of sorts) might one day return to the Siberian steppe.

    If mammoth revival seems impossible, consider this: A team of Russian and Korean genetic engineers is searching for fully intact mammoth DNA to simply clone the animal. In June an expedition uncovered some liquid mammoth blood in a well-preserved carcass in Siberia. The blood sample is now in Seoul, at the labs of the Sooam Biotech Research Foundation, a private organization that is developing techniques for dog cloning.

    While many researchers are skeptical that the Seoul-based group will ever get enough high quality mammoth DNA to clone one, cloning is a viable de-extinction technique for more recently deceased species. The gastric brooding frog is one example. Another is the Pyrenean ibex. In fact, one ibex clone has already been born.

    Woolly Mammoth. Image: Wikicommons

    The Pyrenean ibex, also known as a bucardo, was a kind of mountain goat that once inhabited the rugged terrain between Spain and France. A large creature weighing up to 220 pounds, the bucardo had long horns that swept back from its head and then curled frontward. In the nineteenth century, the population began to decline precipitously—the victim of human hunting and competition from domesticated goats and sheep. The last bucardo, christened “Celia” by biologists, died in 1999 a tree fell on her.

    Before Celia perished, scientists took several tissue samples from the animal and preserved them. A team led by Dr. José Folch from the Centre of Food Technology and Research of Aragon began trying to create a clone from Celia’s DNA. In 2003 the scientists succeeded in getting a surrogate mother to bring a clone to term. The cloned bucardo, however, had a short and miserable life. It was born with a massive lump in its lungs, and died just 10 minutes after coming into the world.

    As the bucardo experience shows, cloning is far from a perfected science. But steady improvements in the technique open up the possibility of one day bringing back a host of extinct species. The San Diego Zoo’s “frozen zoo” has preserved the DNA of hundreds of mammals, birds, amphibians and fish, many of them threatened or endangered. On the botanical front, the Svalbard seed vault in Norway preserves thousands of varieties of food crops. If (or when) some of those species go extinct, and if (or when) cloning becomes more reliable, such cryonic arks will be essential for reviving lost plants and animals.

    Other scientists, meanwhile, are experimenting with back breeding to revive extinct species. To understand back breeding, think of any selective breeding program used to prioritize certain traits—only in this case it’s running evolution in reverse. A Dutch group called Stichting Taurus is using back breeding to revive the auroch. The massive species of cattle (six feet tall at the shoulder and weighing more than a ton) once roamed throughout Europe its likeness appears on the cave paintings at Lascaux. Then came the now-familiar story of habitat destruction and human hunting. The last one died in Poland in 1627. But much of the auroch’s genetic code remains in today’s cow breeds, for example in the large and wild Heck cattle. The Dutch scientists are using DNA samples from auroch bones and teeth to figure out its exact genetic code. Then they are breeding cattle to select for those auroch genes. If all goes according to plan, each successive generation should look more like the ancient auroch.

    How close are we to actually reviving a lost species and returning it to the wild? It depends. While a reborn gastric brooding frog appears imminent, a genetically diverse herd of wooly mammoths is probably a century away. Even the passenger pigeon will take some time. “If everything went smoothly and almost idealistically perfect, it would be good to have some in the wild in the next 25 years,” Ben Novak says. “I think in 50 to 100 years you might start to see some flocks of significant size.”

    As the researchers toil in their labs, the job of popularizing de-extinction has been taken up by Stewart Brand, the charismatic and controversial environmental thinker whose Whole Earth Catalog was a kind of lifestyle bible for seventies-era greens. In late May, Brand delivered an hour-long presentation about revival biology to a packed house of several hundred people at the San Francisco Jazz Center. Brand is tall, lanky and, at 74, still super vigorous, and the talk—part science seminar, part history lesson, part sentimental appeal—was a rousing advertisement for de-extinction’s potential.

    “Biotech is about to liberate conservation, or at least part of it, in a spectacular way,” he said at the beginning of his presentation. Then, after showing grainy, black and white film footage of the last known Tasmanian tiger, Brand intoned: “We see what we’ve lost, and we just mourn. Well, don’t mourn—organize.”

    In Brand’s telling, it was he and his wife, Ryan Phelan, who coalesced the disparate species revival efforts into an international de-extinction movement. Phelan is a successful biomedical entrepreneur who, in the early aughts, started one of the first companies, DNA Direct, that offered individuals genetic testing over the Internet. In the course of her work Phelan got to know George Church, a Harvard geneticist who is a leader in the field of synthetic biology. During a Cambridge dinner with Church, it became clear to Brand and Phelan that species revival was not just possible, but probable. So Church and the couple organized a meeting at the Wyss Institute in Boston to discuss bringing back the passenger pigeon. Buoyed by the encouraging talk they heard there, Brand and Phelan then connected with the National Geographic Society, which in the fall of 2012 hosted a closed-door meeting of molecular and conservation biologists in Washington, DC. The meeting was, by all accounts, exciting Church said it reminded him of the 1984 meeting in Alta, UT that started the Human Genome Project. After that came a National Geographic cover story and a widely viewed TEDx seminar, all designed, Brand said, so that the “public discourse [about de-extinction] would not be simpleminded.”

    Brand’s talk at the San Francisco Jazz Center clearly was also part of that effort, an attempt to inoculate de-extinction against some of the criticisms that have started to arise. “Why bring vanished creatures back to life?” he said. “It will be expensive and difficult. It will take decades. It won’t always succeed. So why even try?” The reasons, he said, are the same ones that motivate us to go to great lengths to protect endangered species: “To preserve biodiversity, to restore diminished ecosystems, to advance the science of preventing extinctions, and to undo harm that humans have caused in the past.”

    Brand was especially careful to head off any suggestions that synthesized species wouldn’t be as valuable as the natural originals. “Will there be something wrong with those passenger pigeons if they have band-tailed traces in them?” Brand asked, and then quickly brushed away such concerns. “We waste our time getting purist about genomes. Most of the American bison we protect have some cattle genes in them, and it makes no difference in their look or behavior.”

    De-extinction, Brand argued, could rescue conservationism from a “kind of hopelessness” in which many people see the natural world as irrevocably “broken.” “Conservation focuses too much on reclaiming the past,” he proclaimed. “It needs to be about creating an exciting vision of the future.”

    He then made a moral plea. If de-extinction is technically possible, we have an obligation to attempt it: “Humans have made a huge hole in nature over the last 10,000 years. Now we have the ability to repair some of the damage.” Brand closed with an aphorism inspired by a Gary Snyder interpretation of Zen Buddhism: “Part of ‘do no harm’ is ‘undo harm.’ … Want to try it?”

    Altogether, it was a convincing presentation. At least in that moment, I did want to try it. To see a wooly mammoth in the flesh—that would be awesome. To bring back the passenger pigeon—that would be an act of poetic justice. Only a killjoy would object.

    And yet … I couldn’t shake the feeling that this was more complicated than Brand had made it sound. Bringing a species back from the dead might be possible, but recreating the ecosystem in which it once lived would be far more difficult. In place of an endling we might have an ecological orphan, stranded outside of its time. A revived species would be a wonderful curiosity—but, I worried, it would be no cure for the extinctions we continue to cause.

    I didn’t have to wait long to share my concerns. Brand and Phelan had organized a private dinner right after the presentation, and I was invited to attend. The gathering took place at the Hayes Street Grill, a San Francisco institution that is a favorite spot for people on their way to the opera or ballet. There were 19 of us: a handful of Silicon Valley venture capitalists, a bunch of techies, some of Brand’s friends, plus the eco-futurist Alex Steffen and Kevin Kelly, the founding editor of Wired . We had the place all to ourselves. Brand sat himself at the center of the table and then plopped onto the white tablecloth a stuffed wooly mammoth that he had used as a prop during his talk. With a mischievous gleam in his eyes, it was obvious how he had fit in as one of Ken Kesey’s Merry Pranksters.

    For her part, Phelan meant business. A striking blonde with soft blue eyes, Phelan carries herself with the easy confidence of someone who has been a stranger to failure. Her professional successes, however, haven’t infected her with arrogance. She knows how much she doesn’t know, and she’s eager to listen to conflicting points of view. As we perused the menu, Phelan issued a challenge: “I want to go around the table, and I want each of you to share your concerns. What’s your biggest worry about de-extinction? Because we have to get this right. We need to make sure we do the cautionary vigilance.”

    No one held back. During the next two hours, the dinner conversation touched on all of the main de-extinction criticisms that I would hear from biologists and environmental activists in the following weeks. The objections go like this:

    Charismatic necrofauna?

    The first complaint about revival biology is that it will distract from the less glamorous work of protecting threatened habitats and endangered, but still extant, species. Some people have argued that the conservation movement has done the public a disservice by focusing so much on especially cuddly or cool animals—“charismatic megafauna” like pandas, tigers and wolves. To truly preserve wildlife, most conservation biologists agree, we need to prioritize saving whole ecosystems. With their overwrought enthusiasm for the wooly mammoth and the passenger pigeon, the de-extinction proponents just fuel that single-species myopia. At the Hayes Street Grill dinner, Alex Steffen coined a neologism for this: “charismatic necrofauna.”

    “I mean, if we had a passenger pigeon, where the hell would we put it?” Duke University’s Stuart Pimm said to me later in an interview. “The more obvious case is the Pyrenean ibex. They were hunted to extinction. If you brought it back, that would be the most expensive cabrito those Basques have ever eaten. You have to have a place to put them back. It’s even worse than that, because it distracts you from the fact that it’s not about species—it’s about ecosystems. If you had spotted owls in a bottle, would that solve the problem of them going extinct in the Pacific Northwest? No, because you’re still destroying the forests.”

    If anything, de-extinction boosters have only fanned this anxiety. Take bird enthusiast Ben Novak. His fetish for the passenger pigeon and his personal peculiarities (he wears his hair completely shorn on one side, chin length on the other) give him the air of one of those eccentric nineteenth-century English citizen-explorers who were dead set on their goals—no matter whether the goals were scientifically important. In our interview he acknowledged that the Long Now Foundation is focused on the pigeon in part because it’s attention grabbing and, well, fundable. “Our goal is to get people behind the goal of de-extinction,” he said. “We had proposed doing proof-of-concept work in a way that would use two living rats and an extinct species of rat, because the technology is much farther along for the cellular work with those species. But few people really care to work on a rat for a subject like this.”

    Tasmanian tiger. Image: Rod Scott

    Here you go, Senator Inhofe.

    A second worry centers on how the public might come to perceive de-extinction. What if people get the idea that, since we are able to bring back disappeared species, we no longer have to worry about wiping out plants and animals? De-extinction could set up a kind of moral hazard—people may be willing to take more risks with the environment, believing there is no price to be paid. The mere possibility of revival biology could give rhetorical cover to the forces hell-bent on resource extraction at any cost. “What I’m afraid of is that there will be people who will say, ‘We don’t have to worry about extinction anymore,’” David Ehrenfeld, a professor of biology at Rutgers, told me. “You know right away which members of Congress will be saying that.”

    Brand and Phelan take this complaint seriously. “The worst case scenario would be one in which people get cavalier about extinction,” Phelan said to me. And that, Brand says, “would be like giving up on exercise and good diet because you hear the costs of heart surgery are coming down.”

    The problem is that not everyone is as conscientious as a couple who live on a houseboat in Sausalito. American politics in the Digital Age is a game of instant telephone Brand and Phelan’s thoughtfulness won’t translate very far. Some political operatives might cynically use the possibility of de-extinction to advance more logging, mining or oil drilling. Alex Steffen warned: “I guarantee you there are people in DC who are working late tonight making a plan for using this to push a political agenda of continued destruction.”

    Ceci n'est pas une pipe.

    If it looks like a passenger pigeon and coos like a passenger pigeon, but is largely made up of band-tailed pigeon genes, is it really a passenger pigeon? Or just a representation of one? No one I spoke with felt that a revived species would have to be 100 percent pure. Still, I heard doubts about the value of something that would be, in the words of Stanley Temple, a professor of environmental studies at University of Wisconsin and a fellow at the Aldo Leopold Center, “a chimera of a pigeon. Or a mammoth that is part mammoth, part Asian elephant.” At some point the original gene pool could be so watered down that the exercise might be worthless.

    Genetics and synthetic biology have come a long way in the last decade, but they remain inexact sciences. “DNA is not an instruction manual,” Rutgers’ Ehrenfeld told me. “It’s kind of like a list of ingredients. Like a dictionary of sorts.”

    The emerging science of epigenetics further complicates the issue. Researchers have found that the genetic prompts encoded within a DNA strand can switch on and off depending upon various factors. For example, an obese and stressed parent will pass to its progeny different characteristics than a slim and thriving parent. The few remaining passenger pigeons from which we have tissue samples—birds that lived in small, fractured flocks—might not be representative of the passenger pigeon in its billion-strong prime.

    But even skeptics say the molecular work being done by the revival biologists could assist traditional species conservation. Advances in genomic sequencing might, for instance, resolve genetic bottlenecks in critically endangered species like the northern white rhinoceros. “If they want to recover ancient DNA and see what they might find, that could be an addition to genetic diversity [of still living species],” Temple said. “To me, that’s almost more exciting than bringing back a passenger pigeon.”

    Flying purple people eaters.

    Embedded within the specific concerns are harder-to-pin-down anxieties about the abuse of genetic engineering and synthetic biology. Simply put, when we tinker with the building blocks of life, we can’t be sure the experiments won’t get away from us. “They [the species revivalists] assume a kind of omniscience that we just don’t have as ecologists,” Ehrenfeld said. “We just can’t predict whether a species that has been translocated will be invasive. … This is techno-optimism of the worst sort.”

    Some people worry that the well meaning de-extinction efforts could be a stepping-stone to more diabolical, Dr. Moreau-like tinkering. After Brand’s presentation, Ben Novak, speaking on stage, casually mentioned the potential of creating “customized species.” Harvard geneticist George Church (“a mad scientist out of Central Casting,” in the words of one person I spoke with) is even more cavalier. In his book Regenesis , he writes: “Genomic technologies will permit us … to take evolution to places where it has never gone, and where it would probably never go if left to its own devices.”

    Such talk makes even some of Brand’s backers uneasy. One of the venture capitalists at the Hayes Street Grill dinner said he feared people creating “flying purple people-eaters” in their garages—something along the lines of the out-of-control artificial species in Margaret Atwood’s cli-fi dystopian novel Oryx and Crake . This isn’t an academic concern. In May a group of biotechnology hobbyists raised nearly half a million dollars on Kickstarter to fund the lab creation of glow-in-the-dark plants each person who pledged more than $40 was promised “seeds to grow a glowing plant at home.”

    The species revivalists grow impatient when they hear criticisms of synthetic biology. “This is what we do—we explore, we make progress, we change how we interact with the world, and we shape it around us,” Novak says. Phelan argues: “We are already engineering. Engineering is happening.”

    True enough. But it’s worth remembering that engineering isn’t infallible. Take, as just one example, the new San Francisco-Oakland Bay Bridge. The beautifully designed suspension bridge is billions of dollars over budget and, before a single car has passed over it, already busted because of some faulty bolts. Human engineering is, indeed, a marvel—blemished only by the inevitability of human error.

    Hank Greeley is an academic’s academic, the kind of thinker who is able to see four sides to every coin. A professor of law at Stanford University and the director of the school’s Center for Law and the Biosciences, Greeley specializes in teasing out the implications of the emerging life sciences. It’s a position, he says, that often gets him in trouble from all sides of the genetic engineering debates. “I have either the fortune or misfortunate trait of heading toward the middle of any topic,” he told me recently.

    Of the 25 presentations delivered at TEDx De-Extinction, Greeley’s was among the most thoughtful. The law professor went through de-extinction’s pros and cons and asked whether it should be considered “hubris or hope.” Then he answered with an equivocal, “yes, a little bit of both.” After weighing the evidence, Greeley said he was in favor of de-extinction because of the way in which it would spark a “sense of wonder. It would be awe-inspiring to see a wooly mammoth. … It would be like the first time I turned that corner and saw Yosemite Valley spread out before me.”

    This is a common refrain among the species revivalists. Novak says his work is hopeful and “humanistic” in a way “similar to the space race.” Phelan told me that de-extinction could deliver to conservationism a jolt of “hope and positive energy.” In his San Francisco presentation, Brand promised: “The current generation of children will experience the return of some remarkable creatures in their lifetime.” And in that achievement “they might see our relation to nature as something other than tragic.”

    I’m sorry, but I’m just not buying it. De-extinction is neat, I agree. It won’t, however, make a meaningful contribution to the global conservation movement.

    There’s no doubt that a revived giant ground sloth would be awesome, in the truest sense of the word. But I doubt such a sight would revive a wonder with the nonhuman world and, in the process, reinvigorate efforts to protect that world. Why? Simply because of the difference in how we experience a man-made wonder and a natural one. The amazement we experience with our technological gee-gaws (remember the first iPhone you saw?) is one thing. The amazement we experience with the surprise at natural forms (remember the first time you visited the Grand Canyon?) is another.

    When I shared this concern with Greeley, he took it seriously—and then dismissed it. “Wonderment is culturally conditioned,” he said. “Wonder varies. I’m not sure there’s a difference between the wonder inspired by nature and the wonder inspired by the Manhattan skyline or the Parthenon.”

    I think Greeley is wrong. Not to be too prissy about it, but when it comes to the objects of our wonder, the distinction makes a difference. The Manhattan skyline at night amazes us with the scale of human invention the Milky Way amazes us with the scale of the universe. They are both an arrangement of lights, but while the first makes humanity seem huge, the second makes us feel small. The difference matters because it influences how we think about our place on this planet. The skyline is good for illustrating our power the starscape teaches us humility.

    The species revivalists overestimate de-extinction’s contribution to conservationism because they misunderstand what conservation is really about. Brand, Novak and Phelan say humans have always been creators and engineers, and they are not wrong. But that fact adds nothing to the ethic or practice of conservation. Taking some parts of the nonhuman world and protecting them from our unruly desires is, above all, an exercise in restraint—not creation. Conservation is about forbearance. It’s a demonstration of the discipline to leave well enough alone.

    Restraint, Discipline, Humility, Forbearance. I know—those are old-fashioned virtues, passé in the epoch of the Anthropocene. Yet they remain the essential counterweights to those who would pave whatever they can for the sake of a buck.

    “We are as gods and might as well get good at it” was the famous epigram of Stewart Brand’s Whole Earth Catalog. Forty-five years later, the possibility of de-extinction makes the line more true than ever. Will playing God by raising species from the grave make us better conservationists? Unlikely. The techno-fix of de-extinction will, in fact, be awe-inspiring. But let’s not pretend that human inventions will make nonhuman creation seem more deserving of our care and protection.

    If we truly want our relation to nature to be “something other than tragic,” what that will require, most of all, is for us to finally, belatedly get good at behaving like something less than gods.

    Visit EcoWatch’s BIODIVERSITY page for more related news on this topic.


    The problems with a warp drive

    There were some problems though. Most important was that this "Alcubierre drive" required lots of "exotic matter" or "negative energy" to work. Unfortunately, there's no such thing. These are things theorists dreamed up to stick into the GR equations in order to do cool things like make stable open wormholes or functioning warp drives.

    It's also noteworthy that researchers have raised other concerns about an Alcubierre drive — like how it would violate quantum mechanics or how when you arrived at your destination it would destroy everything in front of the ship in an apocalyptic flash of radiation.


    Contents

    Remains of various extinct elephants were known by Europeans for centuries, but were generally interpreted, based on biblical accounts, as the remains of legendary creatures such as behemoths or giants. They were thought to be remains of modern elephants that had been brought to Europe during the Roman Republic, for example the war elephants of Hannibal and Pyrrhus of Epirus, or animals that had wandered north. [2] The first woolly mammoth remains studied by European scientists were examined by Hans Sloane in 1728 and consisted of fossilised teeth and tusks from Siberia. Sloane was the first to recognise that the remains belonged to elephants. [3] Sloane turned to another biblical explanation for the presence of elephants in the Arctic, asserting that they had been buried during the Great Flood, and that Siberia had previously been tropical before a drastic climate change. [4] Others interpreted Sloane's conclusion slightly differently, arguing the flood had carried elephants from the tropics to the Arctic. Sloane's paper was based on travellers' descriptions and a few scattered bones collected in Siberia and Britain. He discussed the question of whether or not the remains were from elephants, but drew no conclusions. [5] In 1738, the German zoologist Johann Philipp Breyne argued that mammoth fossils represented some kind of elephant. He could not explain why a tropical animal would be found in such a cold area as Siberia, and suggested that they might have been transported there by the Great Flood. [6]

    In 1796, French biologist Georges Cuvier was the first to identify the woolly mammoth remains not as modern elephants transported to the Arctic, but as an entirely new species. He argued this species had gone extinct and no longer existed, a concept that was not widely accepted at the time. [2] [7] Following Cuvier's identification, German naturalist Johann Friedrich Blumenbach gave the woolly mammoth its scientific name, Elephas primigenius, in 1799, placing it in the same genus as the Asian elephant. This name is Latin for "the first-born elephant". Cuvier coined the name Elephas mammonteus a few months later, but the former name was subsequently used. [8] In 1828, the British naturalist Joshua Brookes used the name Mammuthus borealis for woolly mammoth fossils in his collection that he put up for sale, thereby coining a new genus name. [9]

    Where and how the word "mammoth" originated is unclear. According to the Oxford English Dictionary, it comes from an old Vogul word mēmoŋt, "earth-horn". [10] It may be a version of mehemot, the Arabic version of the biblical word "behemoth". Another possible origin is Estonian, where maa means "earth", and mutt means "mole". The word was first used in Europe during the early 17th century, when referring to maimanto tusks discovered in Siberia. [11] American president Thomas Jefferson, who had a keen interest in palaeontology, was partially responsible for transforming the word "mammoth" from a noun describing the prehistoric elephant to an adjective describing anything of surprisingly large size. The first recorded use of the word as an adjective was in a description of a wheel of cheese (the "Cheshire Mammoth Cheese") given to Jefferson in 1802. [12]

    By the early 20th century, the taxonomy of extinct elephants was complex. In 1942, American palaoentologist Henry Fairfield Osborn's posthumous monograph on the Proboscidea was published, wherein he used various taxon names that had previously been proposed for mammoth species, including replacing Mammuthus with Mammonteus, as he believed the former name to be invalidly published. [13] Mammoth taxonomy was simplified by various researchers from the 1970s onwards, all species were retained in the genus Mammuthus, and many proposed differences between species were instead interpreted as intraspecific variation. [14] Osborn chose two molars (found in Siberia and Osterode) from Blumenbach's collection at Göttingen University as the lectotype specimens for the woolly mammoth, since holotype designation was not practised in Blumenbach's time. Russian palaeontologist Vera Gromova further proposed the former should be considered the lectotype with the latter as paralectotype. Both molars were thought lost by the 1980s, and the more complete "Taimyr mammoth" found in Siberia in 1948 was therefore proposed as the neotype specimen in 1990. Resolutions to historical issues about the validity of the genus name Mammuthus and the type species designation of E. primigenius were also proposed. [15] The paralectotype molar (specimen GZG.V.010.018) has since been located in the Göttingen University collection, identified by comparing it with Osborn's illustration of a cast. [8] [16]

    Evolution Edit

    The earliest known members of the Proboscidea, the clade which contains modern elephants, existed about 55 million years ago around the Tethys Sea. The closest known relatives of the Proboscidea are the sirenians (dugongs and manatees) and the hyraxes (an order of small, herbivorous mammals). The family Elephantidae existed 6 million years ago in Africa and includes the modern elephants and the mammoths. Among many now extinct clades, the mastodon (Mammut) is only a distant relative of the mammoths, and part of the separate family Mammutidae, which diverged 25 million years before the mammoths evolved. [17] The following cladogram shows the placement of the genus Mammuthus among other proboscideans, based on characteristics of the hyoid bone in the neck: [18]

    Within six weeks from 2005-2006, three teams of researchers independently assembled mitochondrial genome profiles of the woolly mammoth from ancient DNA, which allowed them to confirm the close evolutionary relationship between mammoths and Asian elephants (Elephas maximus). [19] [20] A 2015 DNA review confirmed Asian elephants as the closest living relative of the woolly mammoth. [21] African elephants (Loxodonta africana) branched away from this clade around 6 million years ago, close to the time of the similar split between chimpanzees and humans. [22] A 2010 study confirmed these relationships, and suggested the mammoth and Asian elephant lineages diverged 5.8–7.8 million years ago, while African elephants diverged from an earlier common ancestor 6.6–8.8 million years ago. [23] In 2008, much of the woolly mammoth's chromosomal DNA was mapped. The analysis showed that the woolly mammoth and the African elephant are 98.55% to 99.40% identical. [24] The team mapped the woolly mammoth's nuclear genome sequence by extracting DNA from the hair follicles of both a 20,000-year-old mammoth retrieved from permafrost and another that died 60,000 years ago. [25] In 2012, proteins were confidently identified for the first time, collected from a 43,000-year-old woolly mammoth. [26]

    Since many remains of each species of mammoth are known from several localities, reconstructing the evolutionary history of the genus through morphological studies is possible. Mammoth species can be identified from the number of enamel ridges (or lamellar plates) on their molars primitive species had few ridges, and the number increased gradually as new species evolved to feed on more abrasive food items. The crowns of the teeth became deeper in height and the skulls became taller to accommodate this. At the same time, the skulls became shorter from front to back to minimise the weight of the head. [1] [27] The short and tall skulls of woolly and Columbian mammoths (Mammuthus columbi) were the culmination of this process. [28]

    The first known members of the genus Mammuthus are the African species Mammuthus subplanifrons from the Pliocene, and M. africanavus from the Pleistocene. The former is thought to be the ancestor of later forms. Mammoths entered Europe around 3 million years ago. The earliest European mammoth has been named M. rumanus it spread across Europe and China. Only its molars are known, which show that it had 8–10 enamel ridges. A population evolved 12–14 ridges, splitting off from and replacing the earlier type, becoming the southern mammoth (M. meridionalis) about 2–1.7 million years ago. In turn, this species was replaced by the steppe mammoth (M. trogontherii) with 18–20 ridges, which evolved in eastern Asia around 1 million years ago. [1] Mammoths derived from M. trogontherii evolved molars with 26 ridges 400,000 years ago in Siberia and became the woolly mammoth. [1] Woolly mammoths entered North America about 100,000 years ago by crossing the Bering Strait. [28]

    Subspecies and hybridisation Edit

    Individuals and populations showing transitional morphologies between each of the mammoth species are known, and primitive and derived species coexisted, as well, until the former disappeared. So the different species and their intermediate forms have been termed "chronospecies". Many taxa intermediate between M. primigenius and other mammoths have been proposed, but their validity is uncertain depending on author, they are either considered primitive forms of an advanced species or advanced forms of a primitive species. [1] Distinguishing and determining these intermediate forms has been called one of the most long-lasting and complicated problems in Quaternary palaeontology. Regional and intermediate species and subspecies such as M. intermedius, M. chosaricus, M. p. primigenius, M. p. jatzkovi, M. p. sibiricus, M. p. fraasi, M. p. leith-adamsi, M. p. hydruntinus, M. p. astensis, M. p. americanus, M. p. compressus and M. p. alaskensis have been proposed. [13] [29] [30]

    A 2011 genetic study showed that two examined specimens of the Columbian mammoth were grouped within a subclade of woolly mammoths. This suggests that the two populations interbred and produced fertile offspring. A North American type formerly referred to as M. jeffersonii may be a hybrid between the two species. [31] A 2015 study suggested that the animals in the range where M. columbi and M. primigenius overlapped formed a metapopulation of hybrids with varying morphology. It suggested that Eurasian M. primigenius had a similar relationship with M. trogontherii in areas where their range overlapped. [32]

    In 2021, DNA older than a million years was sequenced for the first time, from two mammoth teeth of Early Pleistocene age found in eastern Siberia. One tooth from Adycha (1-1.3 million years old) belonged to a lineage that was ancestral to later woolly mammoths, whereas the other from Krestovka (1.1-1.65 million years old) belonged to new lineage, possibly a distinct species, perhaps descended from steppe mammoths that had become isolated. The study found that half of the ancestry of Columbian mammoths came from the Krestovka lineage, and the other half from woolly mammoths, with the hybridisation happening more than 420,000 years ago, during the Middle Pleistocene. Later woolly and Columbian mammoths also interbred occasionally, and mammoth species perhaps hybridised routinely when brought together by glacial expansion. These findings were the first evidence of hybrid speciation from ancient DNA. The study also found that genetic adaptations to cold environments, such as hair growth and fat deposits, were already present in the steppe mammoth lineage, and was not unique to woolly mammoths. [33] [34]

    The appearance of the woolly mammoth is probably the best known of any prehistoric animal due to the many frozen specimens with preserved soft tissue and depictions by contemporary humans in their art. Fully grown males reached shoulder heights between 2.7 and 3.4 m (8.9 and 11.2 ft) and weighed up to 6 tonnes (6.6 short tons). This is almost as large as extant male African elephants, which commonly reach a shoulder height of 3–3.4 m (9.8–11.2 ft), and is less than the size of the earlier mammoth species M. meridionalis and M. trogontherii, and the contemporary M. columbi. The reason for the smaller size is unknown. Female woolly mammoths reached 2.6–2.9 m (8.5–9.5 ft) in shoulder heights and were built more lightly than males, weighing up to 4 tonnes (4.4 short tons). A newborn calf would have weighed about 90 kg (200 lb). These sizes are deduced from comparison with modern elephants of similar size. [35] Few frozen specimens have preserved genitals, so the gender is usually determined through examination of the skeleton. The best indication of sex is the size of the pelvic girdle, since the opening that functions as the birth canal is always wider in females than in males. [36] Though the mammoths on Wrangel Island were smaller than those of the mainland, their size varied, and they were not small enough to be considered "island dwarfs". [37] The last woolly mammoth populations are claimed to have decreased in size and increased their sexual dimorphism, but this was dismissed in a 2012 study. [38]

    Woolly mammoths had several adaptations to the cold, most noticeably the layer of fur covering all parts of their bodies. Other adaptations to cold weather include ears that are far smaller than those of modern elephants they were about 38 cm (15 in) long and 18–28 cm (7.1–11.0 in) across, and the ear of the 6- to 12-month-old frozen calf "Dima" was under 13 cm (5.1 in) long. The small ears reduced heat loss and frostbite, and the tail was short for the same reason, only 36 cm (14 in) long in the "Berezovka mammoth". The tail contained 21 vertebrae, whereas the tails of modern elephants contain 28–33. Their skin was no thicker than that of present-day elephants, between 1.25 and 2.5 cm (0.49 and 0.98 in). They had a layer of fat up to 10 cm (3.9 in) thick under the skin, which helped to keep them warm. Woolly mammoths had broad flaps of skin under their tails which covered the anus this is also seen in modern elephants. [39]

    Other characteristic features depicted in cave paintings include a large, high, single-domed head and a sloping back with a high shoulder hump this shape resulted from the spinous processes of the back vertebrae decreasing in length from front to rear. These features were not present in juveniles, which had convex backs like Asian elephants. Another feature shown in cave paintings was confirmed by the discovery of a frozen specimen in 1924, an adult nicknamed the "Middle Kolyma mammoth", which was preserved with a complete trunk tip. Unlike the trunk lobes of modern elephants, the upper "finger" at the tip of the trunk had a long pointed lobe and was 10 cm (3.9 in) long, while the lower "thumb" was 5 cm (2.0 in) and was broader. The trunk of "Dima" was 76 cm (2.49 ft) long, whereas the trunk of the adult "Liakhov mammoth" was 2 metres (6.6 ft) long. [39] The well-preserved trunk of a juvenile specimen nicknamed "Yuka" was described in 2015, and it was shown to possess a fleshy expansion a third above the tip. Rather than oval as the rest of the trunk, this part was ellipsoidal in cross section, and double the size in diameter. The feature was shown to be present in two other specimens, of different sexes and ages. [40]

    Coat Edit

    The coat consisted of an outer layer of long, coarse "guard hair", which was 30 cm (12 in) on the upper part of the body, up to 90 cm (35 in) in length on the flanks and underside, and 0.5 mm (0.020 in) in diameter, and a denser inner layer of shorter, slightly curly under-wool, up to 8 cm (3.1 in) long and 0.05 mm (0.0020 in) in diameter. The hairs on the upper leg were up to 38 cm (15 in) long, and those of the feet were 15 cm (5.9 in) long, reaching the toes. The hairs on the head were relatively short, but longer on the underside and the sides of the trunk. The tail was extended by coarse hairs up to 60 cm (24 in) long, which were thicker than the guard hairs. The woolly mammoth likely moulted seasonally, and the heaviest fur was shed during spring. Since mammoth carcasses were more likely to be preserved, possibly only the winter coat has been preserved in frozen specimens. Modern elephants have much less hair, though juveniles have a more extensive covering of hair than adults. [41] This is thought to be for thermoregulation, helping them lose heat in their hot environments. [42] Comparison between the over-hairs of woolly mammoths and extant elephants show that they did not differ much in overall morphology. [43] Woolly mammoths had numerous sebaceous glands in their skin, which secreted oils into their hair this would have improved the wool's insulation, repelled water, and given the fur a glossy sheen. [44]

    Preserved woolly mammoth fur is orange-brown, but this is believed to be an artefact from the bleaching of pigment during burial. The amount of pigmentation varied from hair to hair and within each hair. [39] A 2006 study sequenced the Mc1r gene (which influences hair colour in mammals) from woolly mammoth bones. Two alleles were found: a dominant (fully active) and a recessive (partially active) one. In mammals, recessive Mc1r alleles result in light hair. Mammoths born with at least one copy of the dominant allele would have had dark coats, while those with two copies of the recessive allele would have had light coats. [45] A 2011 study showed that light individuals would have been rare. [46] A 2014 study instead indicated that the colouration of an individual varied from nonpigmented on the overhairs, bicoloured, nonpigmented and mixed red-brown guard hairs, and nonpigmented underhairs, which would give a light overall appearance. [47]

    Dentition Edit

    Woolly mammoths had very long tusks (modified incisor teeth), which were more curved than those of modern elephants. The largest known male tusk is 4.2 m (14 ft) long and weighs 91 kg (201 lb), but 2.4–2.7 m (7.9–8.9 ft) and 45 kg (99 lb) was a more typical size. Female tusks were smaller and thinner, 1.5–1.8 m (4.9–5.9 ft) and weighing 9 kg (20 lb). For comparison, the record for longest tusks of the African bush elephant is 3.4 m (11 ft). The sheaths of the tusks were parallel and spaced closely. About a quarter of the length was inside the sockets. The tusks grew spirally in opposite directions from the base and continued in a curve until the tips pointed towards each other, sometimes crossing. In this way, most of the weight would have been close to the skull, and less torque would occur than with straight tusks. The tusks were usually asymmetrical and showed considerable variation, with some tusks curving down instead of outwards and some being shorter due to breakage. Calves developed small milk tusks a few centimetres long at six months old, which were replaced by permanent tusks a year later. Tusk growth continued throughout life, but became slower as the animal reached adulthood. The tusks grew by 2.5–15 cm (0.98–5.91 in) each year. Some cave paintings show woolly mammoths with small or no tusks, but whether this reflected reality or was artistic license is unknown. Female Asian elephants have no tusks, but no fossil evidence indicates that any adult woolly mammoths lacked them. [48] [49] [50]

    Woolly mammoths had four functional molar teeth at a time, two in the upper jaw and two in the lower. About 23 cm (9.1 in) of the crown was within the jaw, and 2.5 cm (1 in) was above. The crown was continually pushed forwards and up as it wore down, comparable to a conveyor belt. The teeth had up to 26 separated ridges of enamel, which were themselves covered in "prisms" that were directed towards the chewing surface. These were quite wear-resistant and kept together by cementum and dentine. A mammoth had six sets of molars throughout a lifetime, which were replaced five times, though a few specimens with a seventh set are known. The latter condition could extend the lifespan of the individual, unless the tooth consisted of only a few plates. The first molars were about the size of those of a human, 1.3 cm (0.51 in), the third were 15 cm (6 in) 15 cm (5.9 in) long, and the sixth were about 30 cm (1 ft) long and weighed 1.8 kg (4 lb). The molars grew larger and contained more ridges with each replacement. [51] The woolly mammoth is considered to have had the most complex molars of any elephant. [49]

    Adult woolly mammoths could effectively defend themselves from predators with their tusks, trunks and size, but juveniles and weakened adults were vulnerable to pack hunters such as wolves, cave hyenas and large felines. The tusks may have been used in intraspecies fighting, such as fights over territory or mates. Display of the large tusks of males could have been used to attract females and to intimidate rivals. Because of their curvature, the tusks were unsuitable for stabbing, but may have been used for hitting, as indicated by injuries to some fossil shoulder blades. The very long hairs on the tail probably compensated for the shortness of the tail, enabling its use as a flyswatter, similar to the tail on modern elephants. As in modern elephants, the sensitive and muscular trunk worked as a limb-like organ with many functions. It was used for manipulating objects, and in social interactions. [52] The well-preserved foot of the adult male "Yukagir mammoth" shows that the soles of the feet contained many cracks that would have helped in gripping surfaces during locomotion. Like modern elephants, woolly mammoths walked on their toes and had large, fleshy pads behind the toes. [39]

    Like modern elephants, woolly mammoths were likely very social and lived in matriarchal (female-led) family groups. This is supported by fossil assemblages and cave paintings showing groups. So, most of their other social behaviours probably were similar to those of modern elephants. How many mammoths lived at one location at a time is unknown, as fossil deposits are often accumulations of individuals that died over long periods of time. The numbers likely varied by season and lifecycle events. Modern elephants can form large herds, sometimes consisting of multiple family groups, and these herds can include thousands of animals migrating together. Mammoths may have formed large herds more often, since animals that live in open areas are more likely to do this than those in forested areas. [53] Trackways made by a woolly mammoth herd 11,300–11,000 years ago have been found in the St. Mary Reservoir in Canada, showing that in this case almost equal numbers of adults, subadults, and juveniles were found. The adults had a stride of 2 m (6.6 ft), and the juveniles ran to keep up. [54]

    Adaptations to cold Edit

    The woolly mammoth was probably the most specialised member of the family Elephantidae. In addition to their fur, they had lipopexia (fat storage) in their neck and withers, for times when food availability was insufficient during winter, and their first three molars grew more quickly than in the calves of modern elephants. The expansion identified on the trunk of "Yuka" and other specimens was suggested to function as a "fur mitten" the trunk tip was not covered in fur, but was used for foraging during winter, and could have been heated by curling it into the expansion. The expansion could be used to melt snow if a shortage of water to drink existed, as melting it directly inside the mouth could disturb the thermal balance of the animal. [40] As in reindeer and musk oxen, the haemoglobin of the woolly mammoth was adapted to the cold, with three mutations to improve oxygen delivery around the body and prevent freezing. This feature may have helped the mammoths to live at high latitudes. [55]

    In a 2015 study, high-quality genome sequences from three Asian elephants and two woolly mammoths were compared. About 1.4 million DNA nucleotide differences were found between mammoths and elephants, which affect the sequence of more than 1,600 proteins. Differences were noted in genes for a number of aspects of physiology and biology that would be relevant to Arctic survival, including development of skin and hair, storage and metabolism of adipose tissue, and perceiving temperature. Genes related to both sensing temperature and transmitting that sensation to the brain were altered. One of the heat-sensing genes encodes a protein, TRPV3, found in skin, which affects hair growth. When inserted into human cells, the mammoth's version of the protein was found to be less sensitive to heat than the elephant's. This is consistent with a previous observation that mice lacking active TRPV3 are likely to spend more time in cooler cage locations than wild-type mice, and have wavier hair. Several alterations in circadian clock genes were found, perhaps needed to cope with the extreme polar variation in length of daylight. Similar mutations are known in other Arctic mammals, such as reindeer. [56] [57] A 2019 study of the woolly mammoth mitogenome suggest that these had metabolic adaptations related to extreme environments. [58]

    Diet Edit

    Food at various stages of digestion has been found in the intestines of several woolly mammoths, giving a good picture of their diet. Woolly mammoths sustained themselves on plant food, mainly grasses and sedges, which were supplemented with herbaceous plants, flowering plants, shrubs, mosses, and tree matter. The composition and exact varieties differed from location to location. Woolly mammoths needed a varied diet to support their growth, like modern elephants. An adult of 6 tons would need to eat 180 kg (397 lb) daily, and may have foraged as long as 20 hours every day. The two-fingered tip of the trunk was probably adapted for picking up the short grasses of the last ice age (Quaternary glaciation, 2.58 million years ago to present) by wrapping around them, whereas modern elephants curl their trunks around the longer grass of their tropical environments. And the trunk could be used for pulling off large grass tufts, delicately picking buds and flowers, and tearing off leaves and branches where trees and shrubs were present. The "Yukagir mammoth" had ingested plant matter that contained spores of dung fungus. [59] Isotope analysis shows that woolly mammoths fed mainly on C3 plants, unlike horses and rhinos. [60]

    Scientists identified milk in the stomach and faecal matter in the intestines of the mammoth calf "Lyuba". [61] The faecal matter may have been eaten by "Lyuba" to promote development of the intestinal microbes necessary for digestion of vegetation, as is the case in modern elephants. [62] An isotope analysis of woolly mammoths from Yukon showed that the young nursed for at least 3 years, and were weaned and gradually changed to a diet of plants when they were 2–3 years old. This is later than in modern elephants and may be due to a higher risk of predator attack or difficulty in obtaining food during the long periods of winter darkness at high latitudes. [63]

    The molars were adapted to their diet of coarse tundra grasses, with more enamel plates and a higher crown than their earlier, southern relatives. The woolly mammoth chewed its food by using its powerful jaw muscles to move the mandible forwards and close the mouth, then backwards while opening the sharp enamel ridges thereby cut across each other, grinding the food. The ridges were wear-resistant to enable the animal to chew large quantities of food, which often contained grit. Woolly mammoths may have used their tusks as shovels to clear snow from the ground and reach the vegetation buried below, and to break ice to drink. This is indicated on many preserved tusks by flat, polished sections up to 30 centimetres (12 in) long, as well as scratches, on the part of the surface that would have reached the ground (especially at their outer curvature). The tusks were used for obtaining food in other ways, such as digging up plants and stripping off bark. [64] [65]

    Life history Edit

    The lifespan of mammals is related to their size, and since modern elephants can reach the age of 60 years, the same is thought to be true for woolly mammoths, which were of a similar size. The age of a mammoth can be roughly determined by counting the growth rings of its tusks when viewed in cross section, but this does not account for its early years, as these are represented by the tips of the tusks, which are usually worn away. In the remaining part of the tusk, each major line represents a year, and weekly and daily ones can be found in between. Dark bands correspond to summers, so determining the season in which a mammoth died is possible. The growth of the tusks slowed when foraging became harder, for example during winter, during disease, or when a male was banished from the herd (male elephants live with their herds until about the age of 10). Mammoth tusks dating to the harshest period of the last glaciation 25–20,000 years ago show slower growth rates. [66] [67]

    Woolly mammoths continued growing past adulthood, like other elephants. Unfused limb bones show that males grew until they reached the age of 40, and females grew until they were 25. The frozen calf "Dima" was 90 cm (35 in) tall when it died at the age of 6–12 months. At this age, the second set of molars would be in the process of erupting, and the first set would be worn out at 18 months of age. The third set of molars lasted for 10 years, and this process was repeated until the final, sixth set emerged when the animal was 30 years old. When the last set of molars was worn out, the animal would be unable to chew and feed, and it would die of starvation. A study of North American mammoths found that they often died during winter or spring, the hardest times for northern animals to survive. [68]

    Examination of preserved calves shows that they were all born during spring and summer, and since modern elephants have gestation periods of 21–22 months, the mating season probably was from summer to autumn. [69] δ15N isotopic analysis of the teeth of "Lyuba" has demonstrated their prenatal development, and indicates its gestation period was similar to that of a modern elephant, and that it was born in spring. [70]

    The best-preserved head of a frozen adult specimen, that of a male nicknamed the "Yukagir mammoth", shows that woolly mammoths had temporal glands between the ear and the eye. [71] This feature indicates that, like bull elephants, male woolly mammoths entered "musth", a period of heightened aggressiveness. The glands are used especially by males to produce an oily substance with a strong smell called temporin. Their fur may have helped in spreading the scent further. [72]

    Palaeopathology Edit

    Evidence of several different bone diseases has been found in woolly mammoths. The most common of these was osteoarthritis, found in 2% of specimens. One specimen from Switzerland had several fused vertebrae as a result of this condition. The "Yukagir mammoth" had suffered from spondylitis in two vertebrae, and osteomyelitis is known from some specimens. Several specimens have healed bone fractures, showing that the animals had survived these injuries. [73] An abnormal number of cervical vertebrae has been found in 33% of specimens from the North Sea region, probably due to inbreeding in a declining population. [74] Parasitic flies and protozoa were identified in the gut of the calf "Dima". [75]

    Distortion in the molars is the most common health problem found in woolly mammoth fossils. Sometimes, the replacement was disrupted, and the molars were pushed into abnormal positions, but some animals are known to have survived this. Teeth from Britain showed that 2% of specimens had periodontal disease, with half of these containing caries. The teeth sometimes had cancerous growths. [76]

    The habitat of the woolly mammoth is known as "mammoth steppe" or "tundra steppe". This environment stretched across northern Asia, many parts of Europe, and the northern part of North America during the last ice age. It was similar to the grassy steppes of modern Russia, but the flora was more diverse, abundant, and grew faster. Grasses, sedges, shrubs, and herbaceous plants were present, and scattered trees were mainly found in southern regions. This habitat was not dominated by ice and snow, as is popularly believed, since these regions are thought to have been high-pressure areas at the time. The habitat of the woolly mammoth supported other grazing herbivores such as the woolly rhinoceros, wild horses, and bison. [77] The Altai-Sayan assemblages are the modern biomes most similar to the "mammoth steppe". [78] A 2014 study concluded that forbs (a group of herbaceous plants) were more important in the steppe-tundra than previously acknowledged, and that it was a primary food source for the ice-age megafauna. [79]

    The southernmost woolly mammoth specimen known is from the Shandong province of China, and is 33,000 years old. [80] The southernmost European remains are from the Depression of Granada in Spain and are of roughly the same age. [81] [82] DNA studies have helped determine the phylogeography of the woolly mammoth. A 2008 DNA study showed two distinct groups of woolly mammoths: one that became extinct 45,000 years ago and another one that became extinct 12,000 years ago. The two groups are speculated to be divergent enough to be characterised as subspecies. The group that became extinct earlier stayed in the middle of the high Arctic, while the group with the later extinction had a much wider range. [83] Recent stable isotope studies of Siberian and New World mammoths have shown there were differences in climatic conditions on either side of the Bering land bridge, with Siberia being more uniformly cold and dry throughout the Late Pleistocene. [84] During the Younger Dryas age, woolly mammoths briefly expanded into north-east Europe, whereafter the mainland populations became extinct. [85]

    A 2008 genetic study showed that some of the woolly mammoths that entered North America through the Bering land bridge from Asia migrated back about 300,000 years ago and had replaced the previous Asian population by about 40,000 years ago, not long before the entire species became extinct. [86] Fossils of woolly mammoths and Columbian mammoths have been found together in a few localities of North America, including the Hot Springs sinkhole of South Dakota where their regions overlapped. It is unknown whether the two species were sympatric and lived there simultaneously, or if the woolly mammoths may have entered these southern areas during times when Columbian mammoth populations were absent there. [77]

    Modern humans coexisted with woolly mammoths during the Upper Palaeolithic period when the humans entered Europe from Africa between 30,000 and 40,000 years ago. Before this, Neanderthals had coexisted with mammoths during the Middle Palaeolithic, and already used mammoth bones for tool-making and building materials. Woolly mammoths were very important to ice-age humans, and human survival may have depended on the mammoth in some areas. Evidence for such coexistence was not recognised until the 19th century. William Buckland published his discovery of the Red Lady of Paviland skeleton in 1823, which was found in a cave alongside woolly mammoth bones, but he mistakenly denied that these were contemporaries. In 1864, Édouard Lartet found an engraving of a woolly mammoth on a piece of mammoth ivory in the Abri de la Madeleine cave in Dordogne, France. The engraving was the first widely accepted evidence for the coexistence of humans with prehistoric extinct animals and is the first contemporary depiction of such a creature known to modern science. [87]

    The woolly mammoth is the third-most depicted animal in ice-age art, after horses and bison, and these images were produced between 35,000 and 11,500 years ago. Today, more than 500 depictions of woolly mammoths are known, in media ranging from cave paintings and engravings on the walls of 46 caves in Russia, France, and Spain to engravings and sculptures (termed "portable art") made from ivory, antler, stone and bone. Cave paintings of woolly mammoths exist in several styles and sizes. The French Rouffignac Cave has the most depictions, 159, and some of the drawings are more than 2 metres (6.6 ft) in length. Other notable caves with mammoth depictions are the Chauvet Cave, Les Combarelles Cave, and Font-de-Gaume. [88] A depiction in the Cave of El Castillo may instead show Palaeoloxodon, the "straight-tusked elephant". [89]

    "Portable art" can be more accurately dated than cave art since it is found in the same deposits as tools and other ice-age artefacts. The largest collection of portable mammoth art, consisting of 62 depictions on 47 plaques, was found in the 1960s at an excavated open-air camp near Gönnersdorf in Germany. A correlation between the number of mammoths depicted and the species that were most often hunted does not seem to exist, since reindeer bones are the most frequently found animal remains at the site. Two spear throwers shaped as woolly mammoths have been found in France. [88] Some portable mammoth depictions may not have been produced where they were discovered, but could have moved around by ancient trading. [89]

    Exploitation Edit

    Woolly mammoth bones were used as construction material for dwellings by both Neanderthals and modern humans during the ice age. [90] More than 70 such dwellings are known, mainly from the East European Plain. The bases of the huts were circular, and ranged from 8 to 24 square metres (86 to 258 sq ft). The arrangement of dwellings varied, and ranged from 1 to 20 m (3.3 to 65.6 ft) apart, depending on location. Large bones were used as foundations for the huts, tusks for the entrances, and the roofs were probably skins held in place by bones or tusks. Some huts had floors that extended 40 cm (16 in) below ground. Some huts included fireplaces, which used bones as fuel, probably because wood was scarce. Some of the bones used for materials may have come from mammoths killed by humans, but the state of the bones, and the fact that bones used to build a single dwelling varied by several thousands of years in age, suggests that they were collected remains of long-dead animals. Woolly mammoth bones were made into various tools, furniture, and musical instruments. Large bones, such as shoulder blades, were used to cover dead human bodies during burial. [91]

    Woolly mammoth ivory was used to create art objects. Several Venus figurines, including the Venus of Brassempouy and the Venus of Lespugue, were made from this material. Weapons made from ivory, such as daggers, spears, and a boomerang, are known. A 2019 study found that woolly mammoth ivory was the most suitable bony material for the production of big game projectile points during the Late Plesistocene. To be able to process the ivory, the large tusks had to be chopped, chiseled, and split into smaller, more manageable pieces. Some ivory artefacts show that tusks had been straightened, and how this was achieved is unknown. [92] [65]

    Several woolly mammoth specimens show evidence of being butchered by humans, which is indicated by breaks, cut marks, and associated stone tools. How much prehistoric humans relied on woolly mammoth meat is unknown, since many other large herbivores were available. Many mammoth carcasses may have been scavenged by humans rather than hunted. Some cave paintings show woolly mammoths in structures interpreted as pitfall traps. Few specimens show direct, unambiguous evidence of having been hunted by humans. A Siberian specimen with a spearhead embedded in its shoulder blade shows that a spear had been thrown at it with great force. [93] A specimen from the Mousterian age of Italy shows evidence of spear hunting by Neanderthals. [94] The juvenile specimen nicknamed "Yuka" is the first frozen mammoth with evidence of human interaction. It shows evidence of having been killed by a large predator, and of having been scavenged by humans shortly after. Some of its bones had been removed, and were found nearby. [95] A site near the Yana River in Siberia has revealed several specimens with evidence of human hunting, but the finds were interpreted to show that the animals were not hunted intensively, but perhaps mainly when ivory was needed. [96] Two woolly mammoths from Wisconsin, the "Schaefer" and "Hebior mammoths", show evidence of having been butchered by Palaeoamericans. [97] [98]

    Most woolly mammoth populations disappeared during the late Pleistocene and early Holocene, alongside most of the Pleistocene megafauna (including the Columbian mammoth). This extinction formed part of the Quaternary extinction event, which began 40,000 years ago and peaked between 14,000 and 11,500 years ago. Scientists are divided over whether hunting or climate change, which led to the shrinkage of its habitat, was the main factor that contributed to the extinction of the woolly mammoth, or whether it was due to a combination of the two. Whatever the cause, large mammals are generally more vulnerable than smaller ones due to their smaller population size and low reproduction rates. Different woolly mammoth populations did not die out simultaneously across their range, but gradually became extinct over time. Most populations disappeared between 14,000 and 10,000 years ago. The last mainland population existed in the Kyttyk Peninsula of Siberia 9,650 years ago. [99] [100] A small population of woolly mammoths survived on St. Paul Island, Alaska, well into the Holocene [101] [102] [103] with the most recently published date of extinction being 5,600 years B.P. [104] The last known population remained on Wrangel Island in the Arctic Ocean until 4,000 years ago, well into the start of human civilization and concurrent with the construction of the Great Pyramid of ancient Egypt. [105] [106] [107] [108]

    DNA sequencing of remains of two mammoths, one from Siberia 44,800 years BP and one from Wrangel Island 4,300 years BP, indicates two major population crashes: one around 280,000 years ago from which the population recovered, and a second about 12,000 years ago, near the ice age's end, from which it did not. [109] The Wrangel Island mammoths were isolated for 5000 years by rising post-ice-age sea level, and resultant inbreeding in their small population of about 300 to 1000 individuals [110] led to a 20% [111] to 30% [108] loss of heterozygosity, and a 65% loss in mitochondrial DNA diversity. [108] The population seems to have subsequently been stable, without suffering further significant loss of genetic diversity. [108] [112] Genetic evidence thus implies the extinction of this final population was sudden, rather than the culmination of a gradual decline. [108]

    Before their extinction, the Wrangel Island mammoths had accumulated numerous genetic defects due to their small population in particular, a number of genes for olfactory receptors and urinary proteins became nonfunctional, possibly because they had lost their selective value on the island environment. [113] It is not clear whether these genetic changes contributed to their extinction. [114] It has been proposed that these changes are consistent with the concept of genomic meltdown [113] however, the sudden disappearance of an apparently stable population may be more consistent with a catastrophic event, possibly related to climate (such as icing of the snowpack) or a human hunting expedition. [115] The disappearance coincides roughly in time with the first evidence for humans on the island. [116] The woolly mammoths of eastern Beringia (modern Alaska and Yukon) had similarly died out about 13,300 years ago, soon (roughly 1000 years) after the first appearance of humans in the area, which parallels the fate of all the other late Pleistocene proboscids (mammoths, gomphotheres, and mastodons), as well as most of the rest of the megafauna, of the Americas. [117] In contrast, the St. Paul Island mammoth population apparently died out before human arrival because of habitat shrinkage resulting from the post-ice age sea-level rise, [117] perhaps in large measure as a result of a consequent reduction in the freshwater supply. [104]

    Changes in climate shrank suitable mammoth habitat from 7,700,000 km 2 (3,000,000 sq mi) 42,000 years ago to 800,000 km 2 (310,000 sq mi) 6,000 years ago. [118] [119] Woolly mammoths survived an even greater loss of habitat at the end of the Saale glaciation 125,000 years ago, and humans likely hunted the remaining populations to extinction at the end of the last glacial period. [120] [121] Studies of an 11,300–11,000-year-old trackway in south-western Canada showed that M. primigenius was in decline while coexisting with humans, since far fewer tracks of juveniles were identified than would be expected in a normal herd. [54]

    The decline of the woolly mammoth could have increased temperatures by up to 0.2 °C (0.36 °F) at high latitudes in the Northern Hemisphere. Mammoths frequently ate birch trees, creating a grassland habitat. With the disappearance of mammoths, birch forests, which absorb more sunlight than grasslands, expanded, leading to regional warming. [122]

    Woolly mammoth fossils have been found in many different types of deposits, including former rivers and lakes, and in "Doggerland" in the North Sea, which was dry at times during the ice age. Such fossils are usually fragmentary and contain no soft tissue. Accumulations of modern elephant remains have been termed "elephants' graveyards", as these sites were erroneously thought to be where old elephants went to die. Similar accumulations of woolly mammoth bones have been found these are thought to be the result of individuals dying near or in the rivers over thousands of years, and their bones eventually being brought together by the streams. Some accumulations are thought to be the remains of herds that died together at the same time, perhaps due to flooding. Natural traps, such as kettle holes, sink holes, and mud, have trapped mammoths in separate events over time. [123]

    Apart from frozen remains, the only soft tissue known is from a specimen that was preserved in a petroleum seep in Starunia, Poland. Frozen remains of woolly mammoths have been found in the northern parts of Siberia and Alaska, with far fewer finds in the latter. Such remains are mostly found above the Arctic Circle, in permafrost. Soft tissue apparently was less likely to be preserved between 30,000 and 15,000 years ago, perhaps because the climate was milder during that period. Most specimens have partially degraded before discovery, due to exposure or to being scavenged. This "natural mummification" required the animal to have been buried rapidly in liquid or semisolids such as silt, mud, and icy water, which then froze. [124]

    The presence of undigested food in the stomach and seed pods still in the mouth of many of the specimens suggests neither starvation nor exposure is likely. The maturity of this ingested vegetation places the time of death in autumn rather than in spring, when flowers would be expected. [125] The animals may have fallen through ice into small ponds or potholes, entombing them. Many are certainly known to have been killed in rivers, perhaps through being swept away by floods. In one location, by the Byoryolyokh River in Yakutia in Siberia, more than 8,000 bones from at least 140 mammoths have been found in a single spot, apparently having been swept there by the current. [126]

    Frozen specimens Edit

    Between 1692 and 1806, only four descriptions of frozen mammoths were published in Europe. None of the remains of those five were preserved, and no complete skeletons were recovered during that time. [127] While frozen woolly mammoth carcasses had been excavated by Europeans as early as 1728, the first fully documented specimen was discovered near the delta of the Lena River in 1799 by Ossip Schumachov, a Siberian hunter. [128] While in Yakutsk in 1806, Michael Friedrich Adams heard about the frozen mammoth. Adams recovered the entire skeleton, apart from the tusks, which Shumachov had already sold, and one foreleg, most of the skin, and nearly 18 kg (40 lb) of hair. During his return voyage, he purchased a pair of tusks that he believed were the ones that Shumachov had sold. Adams brought all to the Zoological Museum of the Zoological Institute of the Russian Academy of Sciences, and the task of mounting the skeleton was given to Wilhelm Gottlieb Tilesius. [5] [129] This was one of the first attempts at reconstructing the skeleton of an extinct animal. Most of the reconstruction is correct, but Tilesius placed each tusk in the opposite socket, so that they curved outward instead of inward. The error was not corrected until 1899, and the correct placement of mammoth tusks was still a matter of debate into the 20th century. [130] [131]

    The 1901 excavation of the "Berezovka mammoth" is the best documented of the early finds. It was discovered at the Siberian Berezovka River (after a dog had noticed its smell), and the Russian authorities financed its excavation. The entire expedition took 10 months, and the specimen had to be cut to pieces before it could be transported to St. Petersburg. Most of the skin on the head as well as the trunk had been scavenged by predators, and most of the internal organs had rotted away. It was identified as a 35- to 40-year-old male, which had died 35,000 years ago. The animal still had grass between its teeth and on the tongue, showing that it had died suddenly. One of its shoulder blades was broken, which may have happened when it fell into a crevasse. It may have died of asphyxiation, as indicated by its erect penis. One third of a replica of the mammoth in the Museum of Zoology of St. Petersburg is covered in skin and hair of the "Berezovka mammoth". [124] [125]

    By 1929, the remains of 34 mammoths with frozen soft tissues (skin, flesh, or organs) had been documented. Only four of them were relatively complete. Since then, about that many more have been found. In most cases, the flesh showed signs of decay before its freezing and later desiccation. [132] Since 1860, Russian authorities have offered rewards of up to ₽1000 for finds of frozen woolly mammoth carcasses. Often, such finds were kept secret due to superstition. Several carcasses have been lost because they were not reported, and one was fed to dogs. In more recent years, scientific expeditions have been devoted to finding carcasses instead of relying solely on chance encounters. The most famous frozen specimen from Alaska is a calf nicknamed "Effie", which was found in 1948. It consists of the head, trunk, and a fore leg, and is about 25,000 years old. [123]

    In 1977, the well-preserved carcass of a seven- to eight-month-old woolly mammoth calf named "Dima" was discovered. This carcass was recovered near a tributary of the Kolyma River in northeastern Siberia. This specimen weighed about 100 kg (220 lb) at death and was 104 cm (41 in) high and 115 cm (45 in) long. Radiocarbon dating determined that "Dima" died about 40,000 years ago. Its internal organs are similar to those of modern elephants, but its ears are only one-tenth the size of those of an African elephant of similar age. A less complete juvenile, nicknamed "Mascha", was found on the Yamal Peninsula in 1988. It was 3–4 months old, and a laceration on its right foot may have been the cause of death. It is the westernmost frozen mammoth found. [133]

    In 1997, a piece of mammoth tusk was discovered protruding from the tundra of the Taymyr Peninsula in Siberia, Russia. In 1999, this 20,380-year-old carcass and 25 tons of surrounding sediment were transported by an Mi-26 heavy lift helicopter to an ice cave in Khatanga. The specimen was nicknamed the "Jarkov mammoth". In October 2000, the careful defrosting operations in this cave began with the use of hair dryers to keep the hair and other soft tissues intact. [134] [135]

    In 2002, a well-preserved carcass was discovered near the Maxunuokha River in northern Yakutia, which was recovered during three excavations. This adult male specimen was called the "Yukagir mammoth", and is estimated to have lived around 18,560 years ago, and to have been 282.9 cm (9.2 ft) tall at the shoulder, and weighed between 4 and 5 tonnes. It is one of the best-preserved mammoths ever found due to the almost complete head, covered in skin, but without the trunk. Some postcranial remains were found, some with soft tissue. [71]

    In 2007, the carcass of a female calf nicknamed "Lyuba" was discovered near the Yuribey River, where it had been buried for 41,800 years. [62] [136] By cutting a section through a molar and analysing its growth lines, they found that the animal had died at the age of one month. [70] The mummified calf weighed 50 kg (110 lb), was 85 cm (33 in) high and 130 cm (51 in) in length. [137] [138] At the time of discovery, its eyes and trunk were intact and some fur remained on its body. Its organs and skin are very well preserved. [139] "Lyuba" is believed to have been suffocated by mud in a river that its herd was crossing. [62] [140] After death, its body may have been colonised by bacteria that produce lactic acid, which "pickled" it, preserving the mammoth in a nearly pristine state. [62]

    In 2012, a juvenile was found in Siberia, which had man-made cut marks. Scientists estimated its age at death to be 2.5 years, and nicknamed it "Yuka". Its skull and pelvis had been removed prior to discovery, but were found nearby. [95] [141] After being discovered, the skin of "Yuka" was prepared to produce a taxidermy mount. [40] In 2019, a group of researchers managed to obtain signs of biological activity after transferring nuclei of "Yuka" into mouse oocytes. [142]

    In 2013, a well-preserved carcass was found on Maly Lyakhovsky Island, one of the islands in the New Siberian Islands archipelago, a female between 50 and 60 years old at the time of death. The carcass contained well-preserved muscular tissue. When it was extracted from the ice, liquid blood spilled from the abdominal cavity. The finders interpreted this as indicating woolly mammoth blood possessed antifreezing properties. [143]

    Revival of the species Edit

    The existence of preserved soft tissue remains and DNA of woolly mammoths has led to the idea that the species could be recreated by scientific means. Several methods have been proposed to achieve this. Cloning would involve removal of the DNA-containing nucleus of the egg cell of a female elephant, and replacement with a nucleus from woolly mammoth tissue. The cell would then be stimulated into dividing, and inserted back into a female elephant. The resulting calf would have the genes of the woolly mammoth, although its fetal environment would be different. Most intact mammoths have had little usable DNA because of their conditions of preservation. There is not enough to guide the production of an embryo. [144] [145]

    A second method involves artificially inseminating an elephant egg cell with sperm cells from a frozen woolly mammoth carcass. The resulting offspring would be an elephant–mammoth hybrid, and the process would have to be repeated so more hybrids could be used in breeding. After several generations of cross-breeding these hybrids, an almost pure woolly mammoth would be produced. In one case, an Asian elephant and an African elephant produced a live calf named Motty, but it died of defects at less than two weeks old. [146] The fact that sperm cells of modern mammals are viable for 15 years at most after deep-freezing makes this method unfeasible. [145]

    Several projects are working on gradually replacing the genes in elephant cells with mammoth genes. [147] [148] By 2015 and using the new CRISPR DNA editing technique, one team had some woolly mammoth genes edited into the genome of an Asian elephant focusing on cold-resistance initially, [149] the target genes are for the external ear size, subcutaneous fat, hemoglobin, and hair attributes. [150] [151] If any method is ever successful, a suggestion has been made to introduce the hybrids to a wildlife reserve in Siberia called the Pleistocene Park. [152]

    Some researchers question the ethics of such recreation attempts. In addition to the technical problems, not much habitat is left that would be suitable for elephant-mammoth hybrids. Because the species was social and gregarious, creating a few specimens would not be ideal. The time and resources required would be enormous, and the scientific benefits would be unclear, suggesting these resources should instead be used to preserve extant elephant species which are endangered. [145] [153] [154] The ethics of using elephants as surrogate mothers in hybridisation attempts has been questioned, as most embryos would not survive, and knowing the exact needs of a hybrid elephant–mammoth calf would be impossible. [155]

    The woolly mammoth has remained culturally significant long after its extinction. Indigenous peoples of Siberia had long found what are now known to be woolly mammoth remains, collecting their tusks for the ivory trade. Native Siberians believed woolly mammoth remains to be those of giant mole-like animals that lived underground and died when burrowing to the surface. [156] [157] Woolly mammoth tusks had been articles of trade in Asia long before Europeans became acquainted with them. Güyük, the 13th-century Khan of the Mongols, is reputed to have sat on a throne made from mammoth ivory. [127] Inspired by the Siberian natives' concept of the mammoth as an underground creature, it was recorded in the Chinese pharmaceutical encyclopedia, Ben Cao Gangmu, as yin shu, "the hidden rodent". [158]

    The indigenous peoples of North America used woolly mammoth ivory and bone for tools and art. [159] As in Siberia, North American natives had "myths of observation" explaining the remains of woolly mammoths and other elephants the Bering Strait Inupiat believed the bones came from burrowing creatures, while other peoples associated them with primordial giants or "great beasts". [160] [161] [162] Observers have interpreted legends from several Native American peoples as containing folk memory of extinct elephants, though other scholars are sceptical that folk memory could survive such a long time. [160] [162] [163]

    Siberian mammoth ivory is reported to have been exported to Russia and Europe in the 10th century. The first Siberian ivory to reach western Europe was brought to London in 1611. When Russia occupied Siberia, the ivory trade grew and it became a widely exported commodity, with huge amounts being excavated. From the 19th century and onwards, woolly mammoth ivory became a highly prized commodity, used as raw material for many products. Today, it is still in great demand as a replacement for the now-banned export of elephant ivory, and has been referred to as "white gold". Local dealers estimate that 10 million mammoths are still frozen in Siberia, and conservationists have suggested that this could help save the living species of elephants from extinction. Elephants are hunted by poachers for their ivory, but if this could instead be supplied by the already extinct mammoths, the demand could instead be met by these. Trade in elephant ivory has been forbidden in most places following the 1989 Lausanne Conference, but dealers have been known to label it as mammoth ivory to get it through customs. Mammoth ivory looks similar to elephant ivory, but the former is browner and the Schreger lines are coarser in texture. [164] In the 21st century, global warming has made access to Siberian tusks easier, since the permafrost thaws more quickly, exposing the mammoths embedded within it. [165]

    Stories abound about frozen woolly mammoth meat that was consumed once defrosted, especially that of the "Berezovka mammoth", but most of these are considered dubious. The carcasses were in most cases decayed, and the stench so unbearable that only wild scavengers and the dogs accompanying the finders showed any interest in the flesh. Such meat apparently was once recommended against illness in China, and Siberian natives have occasionally cooked the meat of frozen carcasses they discovered. [166] According to one of the more famous stories, members of The Explorers Club dined on meat of a frozen mammoth from Alaska in 1951. In 2016, a group of researchers genetically examined a sample of the meal, and found it to belong to a green sea turtle (it had also been claimed to belong to Megatherium). The researchers concluded that the dinner had been a publicity stunt. [167] In 2011, the Chinese palaeontologist Lida Xing livestreamed while eating meat from a Siberian mammoth leg (thoroughly cooked and flavoured with salt), and told his audience it tasted bad and like soil. This triggered controversy and gained mixed reactions, but Xing stated he did it to promote science. [168]

    Alleged survival Edit

    There have been occasional claims that the woolly mammoth is not extinct and that small, isolated herds might survive in the vast and sparsely inhabited tundra of the Northern Hemisphere. In the 19th century, several reports of "large shaggy beasts" were passed on to the Russian authorities by Siberian tribesmen, but no scientific proof ever surfaced. A French chargé d'affaires working in Vladivostok, M. Gallon, said in 1946 that in 1920, he had met a Russian fur-trapper who claimed to have seen living giant, furry "elephants" deep into the taiga. [169] Due to the large area of Siberia, that woolly mammoths survived into more recent times cannot be completely ruled out, but all evidence indicates that they became extinct thousands of years ago. These natives likely had gained their knowledge of woolly mammoths from carcasses they encountered and that this is the source for their legends of the animal. [170]

    In the late 19th century, rumours existed about surviving mammoths in Alaska. [169] In 1899, Henry Tukeman detailed his killing of a mammoth in Alaska and his subsequent donation of the specimen to the Smithsonian Institution in Washington, DC. The museum denied the story. [171] The Swedish writer Bengt Sjögren suggested in 1962 that the myth began when the American biologist Charles Haskins Townsend travelled in Alaska, saw Eskimos trading mammoth tusks, asked if mammoths were still living in Alaska, and provided them with a drawing of the animal. [169] Bernard Heuvelmans included the possibility of residual populations of Siberian mammoths in his 1955 book, On The Track Of Unknown Animals while his book was a systematic investigation into possible unknown species, it became the basis of the cryptozoology movement. [172]


    Contents

    Cloning Edit

    Cloning is a commonly suggested method for the potential restoration of an extinct species. It can be done by extracting the nucleus from a preserved cell from the extinct species and swapping it into an egg, without a nucleus, of that species' nearest living relative. [3] The egg can then be inserted into a host from the extinct species' nearest living relative. It is important to note that this method can only be used when a preserved cell is available, meaning it would be most feasible for recently extinct species. [4] Cloning has been used in science since the 1950s. [5] One of the most well known clones is Dolly, the sheep. Dolly was born in the mid 1990s and lived a normal life until she experienced health complications that led to her death. [5] Other animal species known to have been cloned include dogs, pigs, and horses. [5]

    Genome editing Edit

    Genome editing has been rapidly advancing with the help of the CRISPR/Cas systems, particularly CRISPR/Cas9. The CRISPR/Cas9 system was originally discovered as part of the bacterial immune system. [6] Viral DNA that was injected into the bacterium became incorporated into the bacterial chromosome at specific regions. These regions are called clustered regularly interspaced short palindromic repeats, otherwise known as CRISPR. Since the viral DNA is within the chromosome, it gets transcribed into RNA. Once this occurs, the Cas9 binds to the RNA. Cas9 can recognize the foreign insert and cleaves it. [6] This discovery was very crucial because now the Cas protein can be viewed as a scissor in the genome editing process.

    By using cells from a closely related species to the extinct species, genome editing can play a role in the de-extinction process. Germ cells may be edited directly, so that the egg and sperm produced by the extant parent species will produce offspring of the extinct species, or somatic cells may be edited and transferred via somatic cell nuclear transfer. This results in a hybrid between the two species, since it is not completely one animal. Because it is possible to sequence and assemble the genome of extinct organisms from highly degraded tissues, this technique enables scientists to pursue de-extinction in a wider array of species, including those for which no well-preserved remains exist. [3] However, the more degraded and old the tissue from the extinct species is, the more fragmented the resulting DNA will be, making genome assembly more challenging.

    Back breeding Edit

    Back breeding is a form of selective breeding. As opposed to breeding animals for a trait to advance the species in selective breeding, back breeding involves breeding animals for an ancestral characteristic that may not be seen throughout the species as frequently. [7] This method can recreate the traits of an extinct species, but the genome will differ from the original species. [4] Back breeding, however, is contingent on the ancestral trait of the species still being in the population in any frequency. [7] Back Breeding is also a form of artificial selection by the deliberate selective breeding of domestic animals, in an attempt to achieve an animal breed with a phenotype that resembles a wild type ancestor, usually one that has gone extinct. Breeding back is not to be confused with dedomestication.

    Iterative evolution Edit

    A natural process of de-extinction is iterative evolution. This process occurs when a species becomes extinct, but then after some amount of time a different species evolves into an almost identical creature. An example of this process occurred with the white-throated rail. This flightless bird became extinct approximately 136,000 years ago due to an unknown event that caused sea levels to rise, which resulted in the demise of the species. The species reappeared about 100,000 years ago when sea levels dropped, allowing the bird to evolve once again as a flightless species on the island of Aldabra, where it is found to the present day. [8] [9] [10] Also see Elvis taxon.

    The technologies being developed for de-extinction could lead to large advancements in scientific technology and process. This includes the advancement of genetic technologies that are used to improve the cloning process for de-extinction. The technologies could be used to prevent endangered species from going extinct. [11] The study of reintroduced species could also lead to advancements in science. By studying previously extinct animals, cures to diseases could be discovered. Revived species may support conservation initiatives by acting as "flagship species" to generate public enthusiasm and funds for conserving entire ecosystems. [12] [13]

    If de-extinction is prioritized it would lead to the improvement of current conservation strategies. Conservation would be necessary in order to reintroduce a species into the ecosystem. Conservation efforts would be taken initially until the revived population can sustain itself in the wild. [14] De-extinction could also help improve ecosystems that had been destroyed by human development by introducing an extinct species back into an ecosystem to revive it. It is also a question whether reviving species driven to extinction by Humans is an ethical obligation. [15]

    The reintroduction of extinct species could have a negative impact on extant species and their ecosystem. The extinct species' ecological niche may have been filled in its former habitat, making it an invasive species. This could lead to the extinction of other species due to competition for food or other competitive exclusion. It could also lead to the extinction of prey species if they have more predators in an environment that had few predators before the reintroduction of an extinct species. [15] If a species has been extinct for a long period of time the environment they are introduced to could be wildly different from the one that they can survive in. The changes in the environment due to human development could mean that the species may not survive if reintroduced into that ecosystem. [11] A species could also become extinct again after de-extinction if the reasons for its extinction are still a threat. The woolly mammoth would be hunted by poachers just like elephants for their ivory and could go extinct again if this were to happen. Or, if a species is reintroduced into an environment with disease it has no immunity to the reintroduced species could be wiped out by a disease that current species can survive.

    De-extinction is a very expensive process. Bringing back one species can cost millions of dollars. The money for de-extinction would most likely come from current conservation efforts. These efforts could be weakened if funding is taken from conservation and put into de-extinction. This would mean that critically endangered species would start to go extinct faster because there are no longer resources that are needed to maintain their populations. [16] Also, since cloning techniques cannot perfectly replicate a species as it existed in the wild, the reintroduction of the species may not bring about positive environmental benefits. They may not have the same role in the food chain that they did before and therefore cannot restore damaged ecosystems. [17]

    Woolly mammoth Edit

    The existence of preserved soft tissue remains and DNA from woolly mammoths has led to the idea that the species could be recreated by scientific means. Two methods have been proposed to achieve this. The first would be to use the cloning process, however even the most intact mammoth samples have had little usable DNA because of their conditions of preservation. There is not enough DNA intact to guide the production of an embryo. [18] The second method would involve artificially inseminating an elephant egg cell with preserved sperm of the mammoth. The resulting offspring would be an elephant–mammoth hybrid. After several generations of cross-breeding these hybrids, an almost pure woolly mammoth could be produced. However, sperm cells of modern mammals are typically potent for up to 15 years after deep-freezing, which could hinder this method. [19] In 2008, a Japanese team found usable DNA in the brains of mice that had been frozen for 16 years. They hope to use similar methods to find usable mammoth DNA. [20] In 2011, Japanese scientists announced plans to clone mammoths within six years. [21]

    In March 2014, the Russian Association of Medical Anthropologists reported that blood recovered from a frozen mammoth carcass in 2013 would now provide a good opportunity for cloning the woolly mammoth. [19] Another way to create a living woolly mammoth would be to migrate genes from the mammoth genome into the genes of its closest living relative, the Asian elephant, to create hybridized animals with the notable adaptations that it had for living in a much colder environment than modern day elephants. This is currently being done by a team led by Harvard geneticist George Church. [22] The team has made changes in the elephant genome with the genes that gave the woolly mammoth its cold-resistant blood, longer hair, and an extra layer of fat. [22] According to geneticist Hendrik Poinar, a revived woolly mammoth or mammoth-elephant hybrid may find suitable habitat in the tundra and taiga forest ecozones. [23]

    George Church has hypothesized the positive effects of bringing back the extinct woolly mammoth would have on the environment, such as the potential for reversing some of the damage caused by global warming. [24] He and his fellow researchers predict that mammoths would eat the dead grass allowing the sun to reach the spring grass their weight would allow them to break through dense, insulating snow in order to let cold air reach the soil and their characteristic of felling trees would increase the absorption of sunlight. [24] In an editorial condemning de-extinction, Scientific American pointed out that the technologies involved could have secondary applications, specifically to help species on the verge of extinction regain their genetic diversity. [25]

    Pyrenean ibex Edit

    The Pyrenean ibex was a subspecies of Spanish ibex that lived on the Iberian peninsula. While it was abundant through medieval times, over-hunting in the 19th and 20th centuries led to its demise. In 1999, only a single female named Celia was left alive in Ordesa National Park. Scientists captured her, took a tissue sample from her ear, collared her, then released her back into the wild, where she lived until she was found dead in 2000, having been crushed by a fallen tree. In 2003, scientists used the tissue sample to attempt to clone Celia and resurrect the extinct subspecies. Despite having successfully transferred nuclei from her cells into domestic goat egg cells and impregnating 208 female goats, only one came to term. The baby ibex that was born had a lung defect, and lived for only 7 minutes before suffocating from being incapable of breathing oxygen. Nevertheless, her birth was seen as a triumph and has been considered to have been the first de-extinction. [26] In late 2013, scientists announced that they would again attempt to recreate the Pyrenean ibex. A problem to be faced, in addition to the many challenges of reproduction of a mammal by cloning, is that only females can be produced by cloning the female individual Celia, and no males exist for those females to reproduce with. This could potentially be addressed by breeding female clones with the closely related Southeastern Spanish ibex, and gradually creating a hybrid animal that will eventually bear more resemblance to the Pyrenean ibex than the Southeastern Spanish ibex. [27]

    Aurochs Edit

    The aurochs was widespread across Eurasia, North Africa, and the Indian subcontinent during the Pleistocene, but only the European aurochs (Bos primigenius primigenius) survived into historic times. [28] This species is heavily featured in European cave paintings, such as Lascaux and Chauvet cave in France, [29] and was still widespread during the Roman era. Following the fall of the Roman empire, overhunting of the aurochs by nobility caused its population to dwindle to a single population in the Jaktorów forest in Poland, where the last wild one died in 1627. [30] However, because the aurochs is ancestral to most modern cattle breeds, it is possible for it to be brought back through selective or back breeding. The first attempt at this was by Heinz and Lutz Heck using modern cattle breeds, which resulted in the creation of Heck cattle. This breed has been introduced to nature preserves across Europe however, it differs strongly from the aurochs in physical characteristics, and some modern attempts claim to try to create an animal that is nearly identical to the aurochs in morphology, behavior, and even genetics. [31] The TaurOs Project aims to recreate the aurochs through selectively breeding primitive cattle breeds over a course of twenty years to create a self-sufficient bovine grazer in herds of at least 150 animals in rewilded nature areas across Europe. [32] This organization is partnered with the organization Rewilding Europe to help restore balance to European nature. [33] A competing project to recreate the aurochs is the Uruz Project by the True Nature Foundation, which aims to recreate the aurochs through a more efficient breeding strategy and through genome editing, in order to decrease the number of generations of breeding needed and the ability to quickly eliminate undesired traits from the aurochs-like cattle population. [34] It is hoped that aurochs-like cattle will reinvigorate European nature by restoring its ecological role as a keystone species, and bring back biodiversity that disappeared following the decline of European megafauna, as well as helping to bring new economic opportunities related to European wildlife viewing. [35]

    Quagga Edit

    The quagga (Equus quagga quagga) is a subspecies of the plains zebra that was distinct in that it was striped on its face and upper torso, but its rear abdomen was a solid brown. It was native to South Africa, but was wiped out in the wild due to overhunting for sport, and the last individual died in 1883 in the Amsterdam Zoo. [36] However, since it is technically the same species as the surviving Plains zebra, it has been argued that the quagga could be revived through artificial selection. The Quagga Project aims to recreate the animal through the selective or back breeding of plains zebras. [37] It also aims to release these animals onto the western Cape once an animal that fully resembles the quagga is achieved, which could have the benefit of eradicating introduced species of trees such as the Brazilian pepper tree, Tipuana tipu, Acacia saligna, Bugweed Camphor tree, Stone pine, cluster pine Weeping willow and Acacia mearnsii. [38]

    Thylacine Edit

    The thylacine was native to the Australian mainland, Tasmania and New Guinea. It is believed to have become extinct in the 20th century. The thylacine had become extremely rare or extinct on the Australian mainland before British settlement of the continent. The last known thylacine, named Benjamin, died at the Hobart Zoo, on September 7, 1936. He is believed to have died as the result of neglect—locked out of his sheltered sleeping quarters, he was exposed to a rare occurrence of extreme Tasmanian weather: extreme heat during the day and freezing temperatures at night. [39] Official protection of the species by the Tasmanian government was introduced on July 10, 1936, roughly 59 days before the last known specimen died in captivity. [40]

    In December 2017 it was announced in Nature Ecology and Evolution that the full nuclear genome of the thylacine had been successfully sequenced, marking the completion of the critical first step toward de-extinction that began in 2008, with the extraction of the DNA samples from the preserved pouch specimen. [41] The Thylacine genome was reconstructed by using the genome editing method. The Tasmanian devil was used as a reference for the assembly of the full nuclear genome. [42] Andrew J. Pask from the University of Melbourne has stated that the next step toward de-extinction will be to create a functional genome, which will require extensive research and development, estimating that a full attempt to resurrect the species may be possible as early as 2027. [41]

    Passenger pigeon Edit

    The passenger pigeon numbered in the billions before being wiped out due to commercial hunting and habitat loss. The non-profit Revive & Restore obtained DNA from the passenger pigeon from museum specimens and skins however, this DNA is degraded because it is so old. For this reason, simple cloning would not be an effective way to perform de-extinction for this species because parts of the genome would be missing. Instead, Revive & Restore focuses on identifying mutations in the DNA that would cause a phenotypic difference between the extinct passenger pigeon and its closest living relative the band-tailed pigeon. In doing this, they can determine how to modify the DNA of the band-tailed pigeon to change the traits to mimic the traits of the passenger pigeon. In this sense, the de-extinct passenger pigeon would not be genetically identical to the extinct passenger pigeon, but it would have the same traits. The de-extinct passenger pigeon hybrid is expected to be ready for captive breeding by 2024 and released into the wild by 2030. [43]

    A "De-extinction Task Force" was established in April 2014 under the auspices of the Species Survival Commission (SSC) and charged with drafting a set of Guiding Principles on Creating Proxies of Extinct Species for Conservation Benefit to position the IUCN SSC on the rapidly emerging technological feasibility of creating a proxy of an extinct species. [44]


    Woolly mammoths had a horrible and miserable end, study says

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    Woolly mammoths went extinct more than 4,000 years ago, but a new study suggests that the last of the creatures died a horrible and isolated death.

    The study looked at the genome of woolly mammoth remains that were discovered on Wrangel Island in the Arctic Ocean. The genomes contained severe mutations that made their final days difficult, the study added.

    “The key innovation of our paper is that we actually resurrect Wrangel Island mammoth genes to test whether their mutations actually were damaging (most mutations don’t actually do anything),” said the study's lead author, Vincent Lynch, in a statement.

    An artist's illustration depicts a herd of woolly mammoths. (Mauricio Anton/PLoS)

    “Beyond suggesting that the last mammoths were probably an unhealthy population, it’s a cautionary tale for living species threatened with extinction: If their populations stay small, they too may accumulate deleterious mutations that can contribute to their extinction," Lynch added.

    By analyzing the genome, the researchers revealed the mammoths had issues with neurological development, male fertility issues, insulin signaling and an impacted ability to smell, which could have severely impacted their diet.

    Lynch and the other researchers were able to come up with their conclusions by sequencing the DNA of the mammoths found on Wrangel Island and comparing them to two other mammoth groups that lived during that time. They were also compared to modern-day elephants.

    "We know how the genes responsible for our ability to detect scents work,” Lynch added. “So we can resurrect the mammoth version, make cells in culture produce the mammoth gene, and then test whether the protein functions normally in cells. If it doesn’t — and it didn’t — we can infer that it probably means that Wrangel Island mammoths were unable to smell the flowers that they ate.”

    As the number of mammoths declined, interbreeding became more common, increasing the number of problems they had, resulting in a cycle that ultimately led to their demise, the study added.

    The research has been published in the scientific journal Genome Biology and Evolution.

    A separate study published in October 2019 suggested that the isolated habitat, extreme weather events, and potentially, prehistoric man, resulted in the extinction of the mammoths on Wrangel Island.

    Mammoth remains have been found all over the globe in recent months. In June 2018, a mysterious mammoth bone was found on a beach in Loch Ryan in southwest Scotland.

    Two months later, in August 2018, a frozen woolly mammoth was found in Siberia, with researchers theorizing that it may be a new type of species, because of its small stature. It has been dubbed a "Golden mammoth" and could be as much as 50,000 years old.

    LAS VEGAS - SEPTEMBER 30: A woolly mammoth skeleton with 90 percent of its original bones is displayed at the Venetian Resort Hotel Casino September 30, 2009 in Las Vegas, Nevada. (Photo by Ethan Miller/Getty Images) (2009 Getty Images)

    In 2018 archaeologists announced the discovery of a mammoth kill site in Austria, where Stone Age people slaughtered mammoths.

    George Church, a Harvard and MIT geneticist and co-founder of CRISPR is the head of the Harvard Woolly Mammoth Revival team, a project that is in attempting to introduce mammoth genes into the Asian elephant for conservation purposes.

    "The elephants that lived in the past — and elephants possibly in the future — knocked down trees and allowed the cold air to hit the ground and keep the cold in the winter, and they helped the grass grow and reflect the sunlight in the summer," Church told Live Science in May 2018. "Those two [factors] combined could result in a huge cooling of the soil and a rich ecosystem."

    The unearthing of well-preserved woolly mammoth remains and advances in genetic research have fueled discussion that the long-extinct beasts could be cloned. However, the ethics of scientists bringing about the possible “de-extinction” of a species have been hotly debated, with critics saying that resources would be better spent on existing animals.


    Warp speed!

    Ah, the warp drive, that darling of science fiction plot devices. So, what about a warp drive? Is that even a really a thing?

    Let's start with the "warping" part of a warp drive. Without doubt, Albert Einstein's theory of general relativity ("GR") represents space and time as a 4-dimensional "fabric" that can be stretched and bent and folded. Gravity waves, representing ripples in the fabric of spacetime, have now been directly observed. So, yes spacetime can be warped. The warping part of a warp drive usually means distorting the shape of spacetime so that two distant locations can be brought close together — and you somehow "jump" between them.

    This was a basic idea in science fiction long before Star Trek popularized the name "warp drive." But until 1994, it had remained science fiction, meaning there was no science behind it. That year, Miguel Alcubierre wrote down a solution to the basic equations of GR that represented a region that compressed spacetime ahead of it and expanded spacetime behind to create a kind of traveling warp bubble. This was really good news for warp drive fans.


    Scientists are reviving extinct species:


    Return of the beasts

    One single cell. That could be all we need to revive a mammoth. Over the last decade, scientists have been part of a veritable revolution of DNA decoding and sequencing, and soon, they may only need one cell to revive any animal which became extinct during the past 30,000 years.

    or too many of the world’s most iconic animals, top predators, and Ice Age behemoths, there’s only one place you can see them – in a museum. Some displays feature stuffed corpses, others mere wax models. It’s a tragedy.

    Our world has lost thousands of species to natural extinction events and human activity alike. But what if we could bring some of those animals back to life with genetic technology and cloning? Should we undo the mistakes of the past? One thing’s for sure: we are on the cusp of a technologyical revolution that will turn this once-academic question into a real challenge for our future.

    Resurrecting the mammoth, the sabre-tooth tiger, the dodo and the thylacine: it’s no longer a question of if, but when.

    Ibex Resurrects

    This debate gained new traction in 2003, when scientists managed to revive the Pyrenean ibex. One of four mountain goat species, the big, agile animal weighed 100+ kg and featured long, beautifully curved horns.

    In the 1800s, the horns made the animal a major target for hunters, and the population shrank fast. In 1892, its close relative the wild Portuguese ibex went extinct. After that, humans realised the animals needed protection, but it was too late. The last Pyrenean ibex, Celia, died in January 2000. Immediate cause of death was being crushed by a falling tree… but really, her species was killed by hunting and loss of habitat.

    A team of scientists headed by Biology Professor Jose Folch started an extraordinary project in 1989. Several years before cloning hit the world stage in 1996 (thanks to Dolly the sheep), the Spanish scientists set out to save the Pyrenean ibex.

    They took DNA samples from some of the remaining individuals, and when Celia died, her cells too were added to the freezer.

    The scientists studied the ibex’ physiology and discovered that a cross-breed between an ordinary goat and an ibex was an excellent surrogate mother. The scientists transferred cell nuclei with the genetic material of Celia the ibex to empty egg cells from a goat, implanting the cells into 57 surrogate mothers. Seven became pregnant, but only one completed the pregnancy. In 2003, she gave birth to a 2.6 kg Celia clone, but the lungs of the young goat were non-functional, and it died only seven minutes after its birth.

    Bigger toolbox

    Since 2003, cloning technology has developed quickly. Today, cloning is an integral part of the toolbox, and scientists can readily convert skin cells into egg cells, which can be artificially fertilised. Along with improved DNA tech, cloning has opened up brand new opportunities.

    At the most fundamental level, all animals have the same DNA – it only differs in the precise genes that make an embryo develop into a sabre-tooth cat instead of a squirrel. The DNA, which instructs cells to divide and grow into a complete individual, is the same in all living creatures.

    Some animals – like the horse and the donkey – look very similar because they have fewer differences in their DNA. In fact horses and donkeys are so similar they can breed to produce mules. This is the principle that geneticists are hoping to use to resurrect extinct species.

    Interbreeding living horse-like animals is one thing, but if the desired species is already extinct, the task is much more difficult.

    Still, If a scientist commands the fully sequenced DNA of an animal species, he has, in principle, a complete manual of how to revive the animal.

    But the trick is getting that unbroken strand of DNA, Though it is a very stable molecule, DNA has a limited life span. Dinosaur DNA, the youngest of which is 65 million years old, has degraded too far to be useful. But Ice Age animals such as sabretooths and mammoths, which lived up until 12,000 years ago, stand a real chance of returning from the dead.

    A new future in ancient blood

    Resurrecting a mammoth is no longer a theoretical possibility – it is a project which scientists are already working on.

    Earlier this year, a Russian expedition headed by Professor Semyon Grigoryev of the North-Eastern Federal University in Yakutsk announced from Siberia the sensational discovery of blood and muscles in a 12-15,000-year-old, frozen mammoth. Scientists have dreamt of such a find since last year, when they entered into cooperation with colleagues of the Sooam Biotech Research Foundation in Seoul. The body is so well-preserved that the tissue may contain the coveted intact cells or cell nuclei, which are necessary to revive a mammoth by means of cloning.

    A few years ago, Japanese scientists found intact nuclei in the cells of mice, which had been placed in the lab’s freezer for 16 years at a temperature of -20 °C. Professor Sayaka Wakayama from the RIKEN research institute in Kobe, who headed the research, transferred the nuclei to emptied mouse egg cells and managed to clone a female mouse, which had offspring. Though 16 years is much less than 12,000, the experiment demonstrated that a frozen body could preserve intact cell nuclei, which may eventually be used to revive the mammoth.

    Passenger pigeon revived

    DNA is also the decisive factor of a revival project, which is to bring the passenger pigeon back to life. In the early 1800s, billions of passenger pigeons existed in America, but over a period of 100 years, hunting and forest felling wiped out the bird. The last wild passenger pigeon was shot in 1900, and only 14 years later, the last passenger pigeon died in the Cincinnati Zoo. Several museums have stuffed passenger pigeons, but none in which scientists can find an intact cell nucleus.

    Scientists headed by biologist Ben Novak from the University of California have had to figure out an alternative strategy involving the passenger pigeon’s closest relative, the band-tailed pigeon. Gene by gene, the scientists intend to edit the band-tailed pigeon’s genetic code until it has been converted into a passenger pigeon genome. A few specific changes will provide the bird with its special features like a red eye and a longer tail.

    For the project to succeed, the scientists need to invent a new cloning technique, as birds cannot be cloned in the ordinary manner. Cloning requires scientists to remove the nucleus of the egg cell, but in birds, the egg is a cell, and though it seems easy to remove the nucleus, it cannot be done without ruining the eggshell and the nucleus.

    At the Roslin Institute in Scotland, biochemist Michael McGrew has invented an alternative method. Instead of inserting the manipulated genome into an egg cell, he inserts it into stem cells, turning them into gametes, which are inserted into the ovaries of a band-tailed pigeon. Thus, he designed a bird with the sex organs of another species. The bird’s offspring will have offspring with the characteristics of both bird species. Consequently, scientists will revive the passenger pigeon by repeating the process and selecting characteristics, until they have a passenger pigeon. Finally, the scientists will teach the pigeons their natural behaviour by means of trained messenger pigeons, among others.

    In principle, the method can be used with many species. For instance, the mammoth could be revived by converting an elephant genome, if scientists do not find an intact, frozen cell nucleus.

    Australian frog the first to return

    The next revived animal will probably be neither the mammoth, nor the passenger pigeon, but an Australian frog, which was discovered in 1972, only to become extinct in the 1980s.

    The gastric-brooding frog, has both a northern and a southern species. The female swallows the eggs, once the male has fertilised them, converting its stomach from an acid bath into a nourishing, protective “womb”. Biologists do not know precisely how the frog does this, but if they find out, doctors may discover new ways of controlling digestion and the release of gastric juice.

    The revival project is headed by Professor Michael Archer of the University of New South Wales, Sydney. The scientists had intact cells from frogs, which were frozen 30+ years ago, and have already cloned the first embryos, and important first stage before tadpole.

    It seems likely that the gastric-brooding frogs were wiped out by a fungal disease introduced by modern humans. The fungus still exists, and so it’s not known for certain if the frogs can ever return to the wild. The same is true for lots of other species such as the baiji- the Yangtse River Dolphin – whose habitat was ruined by pollution.

    Tehcnically, it is not unlikely that we will once again feel the ground shake due to large mammoth herds and watch huge groups of passenger pigeons fly. Perhaps we even have a moral obligation. Humans have caused irrepairable damage to nature. We polluted waterways, cleared forests, and over-exploited animals. But thanks to our technology, we might soon be able to turn back time and revive some of the animal species which we wiped out.


    Watch the video: Η ανακάλυψη της αρχαίας Τενέας.