Scientists Sequence 40,000-Year-Old Mammoth RNA, Unlocking Genetic Clues

Researchers from Stockholm University have successfully isolated and sequenced RNA molecules from Ice Age woolly mammoths, marking the first time such ancient RNA has been recovered. This groundbreaking study, published in the journal Cell, reveals that RNA can remain intact for nearly 40,000 years when preserved in the Siberian permafrost, significantly expanding our understanding of ancient genetics. Emilio Marmol, the lead author of the study, emphasizes the importance of RNA in providing direct evidence of gene activity, stating, 'With RNA, we can obtain direct evidence of which genes are 'turned on,' offering a glimpse into the final moments of life of a mammoth that walked the Earth during the last Ice Age.'

The research team, which included collaboration with SciLifeLab and the Centre for Palaeogenetics, identified distinct patterns of gene expression in muscle tissue from Yuka, a juvenile mammoth that died approximately 40,000 years ago. Among the more than 20,000 protein-coding genes in the mammoth genome, only a portion were active, with RNA molecules detected coding for proteins involved in muscle contraction and metabolic responses to stress. Notably, the findings included signs of cell stress, possibly linked to an attack by cave lions shortly before Yuka's death.

Marc Friedlander, an associate professor at Stockholm University, highlighted the significance of muscle-specific microRNAs found in the mammoth tissues, which are direct evidence of gene regulation occurring in real-time scenarios from ancient times. This discovery is unprecedented, as it confirms the genetic signals originated from mammoths through rare mutations in certain microRNAs, providing a 'smoking-gun demonstration' of their mammoth origin. Bastian Fromm, an associate professor at the Arctic University Museum of Norway, noted that they even detected novel genes based solely on RNA evidence, a feat never before attempted in such ancient remains.

The implications of this study extend beyond woolly mammoths. Love Dalen, a professor of Evolutionary Genomics, indicated that RNA can survive much longer than previously assumed, which opens the possibility of sequencing RNA from other extinct animals and even ancient viruses. Dalen expressed optimism about integrating prehistoric RNA with DNA and proteins, stating that such studies could fundamentally reshape our understanding of extinct megafauna and reveal hidden layers of biology that have been frozen in time.

Woolly mammoths once thrived across the icy plains of Eurasia and North America, adapted to the last Ice Age. However, as the climate warmed, these majestic creatures gradually disappeared, with the last small herds surviving on remote Arctic islands until just 4,000 years ago. This new research not only sheds light on their genetic makeup but also provides a deeper understanding of their biology and the evolutionary processes that shaped them.