Research has unveiled ancient RNA from a juvenile mammoth named Yuka, who perished approximately 40,000 years ago in what is now Siberia. This groundbreaking discovery provides a glimpse into the final moments of this extinct ice age creature. The RNA was meticulously extracted from well-preserved mummified leg tissue, discovered in 2010 in Oyogos Yar, and represents the oldest RNA ever sequenced.
The study, published in the scientific journal Cell, focuses on understanding the mammoth’s genetic activity at the time of its death. According to Love Dalén, a professor of evolutionary genomics at the Centre for Palaeogenetics at Stockholm University, “All the cells in an organism have the same DNA. What differentiates them is the RNA.” This highlights the importance of RNA in determining how various genes are expressed across different cell types.
For long, scientists believed that RNA could not survive extensive periods, unlike DNA, which can last for more than 1 million years. This latest research, however, challenges that notion, as researchers successfully sequenced RNA from three out of ten samples of frozen mammoth tissue, with Yuka’s sample yielding the most comprehensive data regarding gene function at the time of death.
The analysis revealed active messenger RNA molecules, which code for proteins, as well as microRNA, which plays a crucial role in regulating gene activity. Emilio Mármol Sánchez, the study’s lead author and a postdoctoral researcher at the Globe Institute at the University of Copenhagen, emphasized that this research provides insights into the mammoth’s biology just before its demise. He noted, “We do hypothesize that this animal was close to death, and this is manifested in the metabolism of the muscle.”
The findings indicated a predominance of slow-twitch muscle fibers in Yuka’s tissue, suggesting that its muscles were still functioning at the time of death. Among the active proteins identified were titin, linked to muscle elasticity, and nebulin, which plays a role in skeletal muscle contraction. Marc Friedländer, an associate professor in the department of molecular biosciences at Stockholm University, remarked, “The muscle-specific microRNAs we found in mammoth tissues are direct evidence of gene regulation happening in real time in ancient times.”
The implications of this research extend beyond understanding mammoths. Erez Lieberman Aiden, a professor of biochemistry and molecular biology at the University of Texas Medical Branch, noted that the ability to detect tissue-specific expression is impressive and could pave the way for future discoveries in ancient biological research.
Dalén believes that these pioneering techniques could revolutionize scientific research into the past. He stated, “My gut feeling is that methods will improve. There are lots of labs around the world excited about RNA.” Improved methods could also facilitate the study of ancient viruses, which primarily exist in RNA form, and contribute to efforts aimed at resurrecting extinct species. Colossal Biosciences, a Texas-based biotech company, aims to revive species such as the mammoth, dodo, and Tasmanian tiger by editing the genomes of their closest living relatives.
While Yuka’s RNA is the oldest scientists have recovered, it is not the first instance of ancient RNA being sequenced. In 2023, Mármol Sánchez led a study that sequenced RNA from a 130-year-old Tasmanian tiger, and in 2019, a team sequenced RNA from a 14,300-year-old wolf preserved in permafrost. Research has also identified RNA in the tissue of Ötzi the Iceman, a 5,300-year-old mummy found in the Alps.
As the field continues to evolve, Aiden expressed cautious optimism about the significance of this research. He compared it to being a guest at a wedding and pondering the happiness of the marriage, suggesting that it may take time to fully understand the potential of RNA as a reservoir of information regarding extinct organisms.
