Woolly mammoths and living elephants are characterized by major phenotypic differences that have allowed them to live in very different environments. To identify the genetic changes that underlie the suite of woolly mammoth adaptations to extreme cold, we sequenced the nuclear genome from three Asian elephants and two woolly mammoths, and we identified and functionally annotated genetic changes unique to woolly mammoths. We found that genes with mammoth-specific amino acid changes are enriched in functions related to circadian biology, skin and hair development and physiology, lipid metabolism, adipose development and physiology, and temperature sensation. Finally, we resurrected and functionally tested the mammoth and ancestral elephant TRPV3 gene, which encodes a temperature-sensitive transient receptor potential (thermoTRP) channel involved in thermal sensation and hair growth, and we show that a single mammoth-specific amino acid substitution in an otherwise highly conserved region of the TRPV3 channel strongly affects its temperature sensitivity.
Before the world's last woolly mammoth took its final breath, the iconic animals had already suffered from a considerable loss of genetic diversity. These findings, based on a comparison of the first complete genome sequences isolated from two ancient mammoth specimens, are reported in the Cell Press journal Current Biology on April 23.
One of those mammoths, representing the last population on Russia's Wrangel Island, is estimated to have lived about 4,300 years ago. The other specimen, from northeastern Siberia, is about 44,800 years old. The younger of the two specimens showed much lower genetic variation, including large stretches of DNA with no variation whatsoever - the mark of living in a very small population in which related individuals unavoidably mate with each other.
"We found that the genome from one of the world's last mammoths displayed low genetic variation and a signature consistent with inbreeding, likely due to the small number of mammoths that managed to survive on Wrangel Island during the last 5,000 years of the species' existence," says Love Dalén of the Swedish Museum of Natural History.
Researchers from Harvard University have successfully inserted genes from a woolly mammoth into living cells from an Asian elephant, the extinct giant's closest remaining relative.
Harvard geneticist George Church used DNA from Arctic permafrost woolly mammoth samples to copy 14 mammoth genes -- emphasizing those related to its chilly lifestyle.
"We prioritized genes associated with cold resistance including hairiness, ear size, subcutaneous fat and, especially, hemoglobin," Church told The Sunday Times.
Then, using a kind of DNA cut/paste system called CRISPR (clustered regularly interspaced short palindromic repeat), Church dropped the genes into Asian elephant skin cells.
The result? A petri dish of elephant cells functioning normally with mammoth DNA in them, marking the first time mammoth genes have been on the job since the creature went extinct some 4,000 years ago, as Sarah Fecht, from Popular Science, noted.
A new analysis of European archaeological sites containing large numbers of dead mammoths and dwellings built with mammoth bones has led Penn State Professor Emerita Pat Shipman to formulate a new interpretation of how these sites were formed. She suggests that their abrupt appearance may have been due to early modern humans working with the earliest domestic dogs to kill the now-extinct mammoth -- a now-extinct animal distantly related to the modern-day elephant. Shipman's analysis also provides a way to test the predictions of her new hypothesis. Advance publication of her article "How do you kill 86 mammoths?" is available online through Quaternary International.
Spectacular archaeological sites yielding stone tools and extraordinary numbers of dead mammoths -- some containing the remains of hundreds of individuals -- suddenly became common in central and eastern Eurasia between about 45,000 and 15,000 years ago, although mammoths previously had been hunted by humans and their extinct relatives and ancestors for at least a million years. Some of these mysterious sites have huts built of mammoth bones in complex, geometric patterns as well as piles of butchered mammoth bones.
"One of the greatest puzzles about these sites is how such large numbers of mammoths could have been killed with the weapons available during that time," Shipman said. Many earlier studies of the age distribution of the mammoths at these sites found similarities with modern elephants killed by hunting or natural disasters, but Shipman's new analysis of the earlier studies found that they lacked the statistical evaluations necessary for concluding with any certainty how these animals were killed.
Surprisingly, Shipman said, she found that "few of the mortality patterns from these mammoth deaths matched either those from natural deaths among modern elephants killed by droughts or by culling operations with modern weapons that kill entire family herds of modern elephants at once." This discovery suggested to Shipman that a successful new technique for killing such large animals had been developed and its repeated use over time could explain the mysterious, massive collections of mammoth bones in Europe.
The key to Shipman's new hypothesis is recent work by a team led by Mietje Germonpré of the Royal Belgian Institute of Natural Sciences, which has uncovered evidence that some of the large carnivores at these sites were early domesticated dogs, not wolves as generally had been assumed. Then, with this evidence as a clue, Shipman used information about how humans hunt with dogs to formulate a series of testable predictions about these mammoth sites.
There's a mission to bring back one of history's most famous animals, it's already underway, and it's closer to becoming a reality than even some of the most forward-looking minds think it is.
For all the talk and attention it gets, de-extincting an animal isn't exactly easy—it's difficult to clone cells from an animal that has been dead for thousands of years, tougher to turn it into a viable embryo, and, most importantly, more difficult still to find a closely-related animal that can serve as a surrogate mother to give birth to the cloned animal. There's certainly work still being done in that area, but, increasingly, researchers are working to hybridize existing animals with extinct ones in order to create what Brand calls a "2.0" version of the animal.
That's what Harvard synthetic biologist George Church is doing with woolly mammoths. Using a genome editing technique known as CRISPR, Church is working on inserting three key genes from woolly mammoths into Asian elephant cells, with the hope of eventually creating a hybrid between the two that will ideally be more mammoth-like than elephant-like.
The project and technology has been touched on before, most notably in a lengthy New York Times Magazine article from February, but Church tells me that the team has now successfully migrated the three genes, which gave the woolly mammoth its furry appearance, extra layer of fat, and cold-resistant blood. In theory, given what we know about both the woolly mammoth genome and the Asian elephant genome, the final product will be something that more closely resembles the former than the latter.
