By Aylin Woodward

Scientists have extracted RNA from an ancient woolly mammoth that gives new insight into the extinct beasts -- and might one day boost moonshot efforts to resurrect them.

The animal's body was discovered remarkably well-preserved in the northern Siberian permafrost in 2010, some 40,000 years after it died. Researchers first analyzed its DNA in 2019, but hadn't attempted until more recently to extract its more-fragile RNA, which controls which segments of DNA are active.

It is the oldest RNA that scientists have ever sequenced -- about three times older than anything prior, said Love Dalén, professor of evolutionary genomics at Stockholm University and lead author of a recent paper in the journal Cell describing the results.

Though it sounds fanciful, some scientists actually are trying to bring back the woolly mammoth. The biotech firm Colossal Biosciences has garnered attention for its quest to de-extinct the animals by inserting mammoth genes into the DNA of an Asian elephant, its closest living relative.

"While the path to de-extinction might be a little bit longer than most people appreciate, I think this is actually a very important steppingstone on the way," said Marc Friedländer, an RNA biologist from Stockholm University and a co-author of the paper.

Dalén, who is on Colossal Biosciences' scientific advisory board, said the results don't necessarily bring the company closer to the feat. But analyzing RNA from mammoth hair follicles could help pinpoint which genes made woolly mammoths woolly, he said.

He first saw the mammoth calf, named Yuka after where it was found by locals, when visiting Yakutsk, Russia, in 2012.

"The Russians said, 'Come with me, and we'll bring you to see something interesting,'" he said. "They walked me into this room, and there's this dead mammoth lying on an autopsy table."

Yuka's legs were intact, as were the animal's foot pads and trunk, covered in reddish-brown fur. The skull, genitalia and internal organs were missing. Genetic analyses revealed the animal was a male; some of the RNA had come from a Y chromosome.

RNA, or ribonucleic acid, adds another level of insight into an animal beyond DNA, Dalén said, showing which genes are active in a cell at one time. DNA contains the recipe for how to make an organism, but RNA passes along the instructions on how to build and operate it.

"You can see, was an organism healthy? Was it ill? Was it stressed?" said Friedländer.

These critical molecules are unstable, particularly outside the body, but can persist in conditions that are very cold or very dry -- like the Siberian permafrost where Yuka was found.

The researchers examined muscle and skin samples from 10 woolly mammoths, including Yuka, sent to them from Yakutsk. Only three yielded RNA, which the scientists extracted by grinding the tissues into a powder, then mixing them with chemicals that helped break open the cells inside and let them separate out RNA molecules.

Yuka's RNA helped reveal a snapshot of the creature's last moments. Signs of muscle stress and claw marks on the animal's rear suggested Yuka was hunted down by predators, Dalén said. Previous research estimated the mammoth died around the age of 5, judging by its tusks.

"If at some point in the future that we want to bring back the mammoth or other extinct animals, then it's very important to recognize that we need to understand them not just at the DNA level, but also all the other components that make up an animal, like the RNA and the proteins," Friedländer said.

Write to Aylin Woodward at aylin.woodward@wsj.com

(END) Dow Jones Newswires

December 16, 2025 11:00 ET (16:00 GMT)

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