Researchers recovered several hundred RNA transcripts from leg muscle of Yuka, a juvenile woolly mammoth frozen in Siberian permafrost for about 39,000 years, capturing signs of acute cellular stress near death.
Those transcripts included genes tied to muscle contraction and metabolic stress, aligning with earlier evidence that Yuka was attacked by cave lions shortly before dying.
To show the signal was ancient rather than contamination, the team authenticated short microRNAs carrying rare mutations that matched known mammoth genetic markers and muscle-specific activity.
The Cell study does not show RNA routinely survives that long; it establishes that under unusually stable permafrost conditions, RNA can persist for tens of thousands of years and preserve snapshots of cellular activity.