Mammoth RNA molecules sequenced for the first time

In 2010, the thawed carcass of a small woolly mammoth was found in the permafrost on the Oyogos Yar bluff, on the coast of the Dmitry Laptev Strait in northern Yakutia, Russia. The woolly mammoth was nicknamed “Yuka".

A few years later, a group of researchers in Stockholm received a long-awaited delivery — a box containing samples from ten mammoths, including those of Yuka, sent by their scientific partners in Russia.

A study published this year by this international group of scientists shows that Yuka's sample was the most successful out of all ten: researchers managed to extract valuable information from RNA molecules of the ancient animal.

‘While DNA contains information about you as a living creature that doesn’t change throughout your life, RNA molecules particularly reflect what was happening in Yuka’s muscles a few minutes before he died,’ Dr Emilio Mármol, a genomicist at the University of Copenhagen and lead author of a study, told the Barents Observer.

“We found signs of cellular stress in the tissue of this mammoth before he died,” Dr Mármol explained. “We hypothesised that Yuka died in a stressful situation. He was probably hunted by predators. As the body is so well preserved, we can see the scratches on the skin. They are most probably from a cave lion, based on their size and shape.”

Dr Mármol explains that these are the oldest ever recovered RNA sequences and that this is the first time that molecules have been extracted from a woolly mammoth.

“It's a scientific miracle!” Dr Bastian Fromm, a zoologist and evolutionary biologist at the Arctic University Museum of Norway, told the Barents Observer. ‘It is believed that RNA is very unstable, and you cannot actually obtain it from samples that are 40,000 years old. We are very surprised that we managed to do this.”

Dr Bastian Fromm, who is co-author of the study, expressed hope that the new, more sensitive analytical method they used for this research would enable RNA to be extracted from other animals in his museum's collection. This means that we can learn more about the living conditions of other species of animals that became extinct thousands of years ago.

Yuka, a five-year-old baby mammoth, died at the end of the Ice Age - 39,000 years ago.  At first, based solely on an external examination of the genitals, the mammoth was thought to be female. However, DNA and RNA analysis made by Dr Bastian Fromm's team revealed a Y chromosome, indicating that it was male.

The ability to extract both DNA and RNA is attributed to the fact that the permafrost helped preserve the body well, as it froze right after death and had no time to decompose. In addition, Yuka's remains were properly maintained throughout the entire journey to the various labs. 

But now, as the planet warms, the permafrost is thawing. 

“More and more remains of prehistoric animals are being found in Yakutia now as lots of this permafrost is thawing due to climate change,” Dr Emilio Mármol tells the Barents Observer. ‘But the difference with the times of Yuka is that now we are seeing a similar climate change, but ten times faster in time. The changes will be massive for our sons and grandsons, if in a few hundred years the temperature rises just 2 or 3 degrees more.” Dr Mármol said. 

Climate change was also one of the reasons why mammoths went extinct 4,000 years ago. For now, as Dr Mármol explains, his lab is not planning to conduct further mammoth research. One of the reasons why is that "access to precious mammoth samples from Russia is more difficult now due to sanctions".

In 2022, the war in Ukraine put scientific exchanges with Russia on hold. As the mammoth samples had been collected prior to the sanctions being imposed, the study was still conducted in collaboration with Russian scientists.