Scientists have made a remarkable breakthrough by sequencing the oldest RNA ever retrieved from a woolly mammoth named Yuka. This creature lived nearly 39,000 years ago and died as a young mammoth, around 5 or 6 years old. The discovery took place in Siberian permafrost, where Yuka’s remarkably well-preserved remains were found in 2010.
Traditionally, researchers believed RNA couldn’t survive so long because it degrades much faster than DNA. But Yuka’s frozen tissues challenged this old thinking. A team of geneticists from Stockholm University and SciLifeLab were able to extract and analyze pieces of RNA from both the skin and muscle tissues. They discovered important aspects of Yuka’s biological activity just before his death, which offers fascinating insights into his life.
Unlike DNA, RNA reveals which genes were actively at work at any given moment. It shows not just what the mammoth was made of but also what it was doing shortly before it died. For instance, the researchers found RNA linked to muscle contraction and responses to stress, aligning with earlier theories that Yuka may have been attacked by cave lions.
Interestingly, out of ten mammoths studied, only one—Yuka—provided RNA sufficient for sequencing, showcasing his exceptional preservation.
Another exciting aspect of this research is the discovery of microRNAs, which help regulate gene expression without producing proteins. These small molecules are vital for understanding how interactions at the genetic level occurred in real time. According to Marc Friedländer, a molecular bioscientist involved in the project, “The muscle-specific microRNAs we found in mammoth tissues are direct evidence of gene regulation happening in real time in ancient times.” This marks a significant milestone in paleogenomics, proving that useful biological information can indeed be recovered from ancient specimens.
While scientists have successfully sequenced ancient DNA before, sequencing RNA from specimens as old as Yuka has been seen as nearly impossible due to RNA’s quick breakdown. However, the well-preserved state of Yuka’s body shows that under the right conditions, RNA can last much longer than previously thought. Love Dalén, an evolutionary geneticist, mentioned, “This means that we will not only be able to study which genes are ‘turned on’ in different extinct animals, but it will also be possible to sequence RNA viruses preserved in Ice Age remains.”
However, the rarity of such finds cannot be overstated. Out of the ten mammoths examined, only three showed traces of ancient RNA, and just one yielded enough for comprehensive analysis. This underscores the importance of continued exploration of ancient remains, as they hold keys to understanding past life forms and their adaptations.
For more detailed insights into this groundbreaking study, you can check [Cell’s article](https://www.cell.com/cell/fulltext/S0092-8674(25)01231-0?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0092867425012310%3Fshowall%3Dtrue).
