Valerii Plotnikov (left) of the Academy of Sciences of the Republic of Sakha, Yakutsk, Russia, and Daniel Fisher of the University of Michigan examine a woolly mammoth excavated during a 2018 expedition.
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Scientists have recreated the three-dimensional structure of the woolly mammoth’s genetic material.
The achievement, described Thursday in the journal Cell, is reportedly the first time scientists have produced a multidimensional version of the genome of a complex extinct species.
The advances should yield important new insights into the biology of a creature that has long fascinated scientists. In addition, the work could inform efforts to breed a living version of the animal, the researchers and others said.
“It’s exciting,” says Erez Lieberman Aiden, a professor of molecular and human genetics and director of the Center for Genome Architecture at Baylor College of Medicine in Houston. “We think it’s going to be very valuable.”
For years, scientists have been able to look back in time by analyzing fragments of ancient DNA from bones, fossilized teeth, mummies and even hair strands.
“In biology, one of the most powerful tools for understanding the history of life on this planet is ancient DNA,” Aiden says. “It’s an incredibly powerful tool for understanding the history of life.”
But scientists can only learn so much from bits of DNA. That’s why Aiden and his colleagues launched an international effort to recreate the three-dimensional structure of DNA, including chromosomes, from an extinct creature.
“That would allow you to see exactly how that chromosome formed in a living cell, and you could get a deeper understanding of the genomes of ancient and extinct species and how those genomes worked – which genes were turned on and off in certain tissues,” Aiden says.
Looking for mammoth monsters on eBay
The scientists focused on the woolly mammoth, a large, shaggy elephant species that roamed the tundra thousands of years ago.
“Initially, we had embarrassingly bad ideas. I’m a little embarrassed to admit that,” Aiden told NPR. “We said, ‘Oh, you know, that looks like a nice piece of mammoth on eBay. Let’s try that.’ It’s a little embarrassing, right, to tell you that. Ebay is a bad place to get your mammoth samples.”
After five years of searching, the team finally found a well-preserved mammoth specimen: skin from behind the ear of a 52,000-year-old female found freeze-dried in Siberia in 2018.
“It was a piece of mammoth skin that was, you know, woolly. As the name suggests, it was woolly mammoth skin,” said Olga Dudchenko, an assistant professor at the Baylor Center for Genome Architecture who worked on the study. “And that’s actually not as trivial as it sounds, because very often the hair is lost. This one was hairy. And that in itself is an interesting indicator that this is a sample of substantial quality. And that immediately caught our attention.”
Scientists can look at individual mammoth genes
The quality of the sample allowed the team to extract DNA and use a technique called Hi-C to reconstruct the three-dimensional structure of all 28 of the mammoth’s chromosomes, the complete genome of the extinct animal, the researchers reported.
“We were able to sequence the genome of a woolly mammoth, just like people were excited about sequencing their own genomes 25 years ago,” Aiden says. “Now we can do that for animals that have been extinct for a long time. That’s a milestone, of course.”
In addition, the team was able to peer into the genome to find out what individual genes do.
“And it’s really exciting to be able to look at an extinct creature and say, ‘Oh yeah. I can see this gene was turned on. That gene was turned on. This gene was turned off. Oh, isn’t that surprising?'” Aiden says. “It’s exciting to be able to do all these specific things in a woolly mammoth.”
By comparing the mammoth genome with the DNA of modern elephants, scientists have already found clues about what made the woolly mammoth so special. woolly.
“We discussed internally whether we should start a Hair Club for mammoths?” Dudchekno jokes.
Genetic findings could aid efforts to bring back mammoths
But seriously, that insight could help efforts already underway to save some version of the mammoth from extinction by giving modern Asian elephants mammoth traits, such as their hairy appearance, and perhaps even releasing them to graze on the tundra again.
“I think this could help with de-extincting,” says Aiden.
Other scientists praised the work.
“I think it’s really cool,” said Vincent Lynch, an associate professor of biological sciences at the University at Buffalo who was not involved in the study.
But Lynch is not a fan of trying to bring back the mammoth. The unintended consequences could be disastrous, he says. And the money for such a project would be much better spent saving the elephants that still roam the planet today.
“There’s a huge potential for unintended consequences,” Lynch says. “Think about all the other invasive species that are out there in the world. You don’t really know what effect that species is going to have on the environment until it gets there.”
And Karl Flessa, a professor of earth sciences at the University of Arizona, agrees that it is a scientific achievement and that it is foolish to try to bring back the extinct pachyderm.
“The preservation of the genetic architectures of the woolly mammoth is truly remarkable,” Flessa says. “But just because you can do it doesn’t mean you should. A genetically modified Asian elephant is not a woolly mammoth. And releasing one of those animals into the wild would be arrogant and irresponsible.”
Others disagree.
“It is exciting to see that 3D architecture can be preserved in ancient samples. This will help to achieve a complete de novo assembled mammoth genome, which could reveal features of the genome that could be relevant to the extinction of mammoths,” Eriona Hysolli, who is leading a project to create an Asian elephant with mammoth features at Colossal Laboratories & Biosciences in Dallas, told NPR in an email.
Still, Robert Fleischer, a senior scientist at the Center for Conservation Genomics at the Smithsonian’s National Zoo & Conservation Institute in Washington, says it’s an exciting prospect.
“If I was 12 years old and in my high school science class, I would probably think this was cool,” Fleischer says. “And I still think it’s pretty cool.”