The oldest genetic remains in history were discovered in the preserved tissues of a young mammoth, a species that became extinct almost forty thousand years ago. The finding was recently published in the scientific journal Cell and is considered a breakthrough in the field of paleogenetics.
The RNA molecules that were discovered shed new light on the life of the mammoth, known as Yuka, and on the biological processes that occurred in its body during the minutes before it died during the Ice Age.
The Yuka mammoth was discovered in 2010 by ivory hunters on the bank of a river in northern Siberia. Its frozen body was well preserved in the deep layers of the frozen earth, with reddish shades of fur, a deformed snout, and a nearly intact brain. Its tissues reportedly preserved an extremely rare genetic component.
Researchers from Stockholm, Copenhagen, and other research institutes claim that these are the oldest RNA molecules ever found.
RNA molecules are key to reconstructing cellular activity in real time. Unlike DNA, which stores genetic information, RNA represents the activity of genes during life. It tells which genes were active, what was translated into proteins, and what processes were occurring at the moment it was preserved.
Due to their natural fragility, RNA molecules decompose immediately after death and were previously considered a biological relic that could survive thousands of years. The frozen ground of Siberia, however, provided extraordinary conditions that allowed the RNA to be preserved for almost forty thousand years.
Examinations of the sample found that some of the RNA molecules in the Yuka tissues were associated with the activation of genes involved in the development of skeletal muscles.
Equally interesting is the abundance of RNA molecules that indicate extreme stress in the cells shortly before death. The scientists speculate that the Yuka experienced an injury or a struggle with predators, such as cave lions, and then fell into shallow water, where it then died.
These subtle signs created a never-before-seen biological snapshot.
Researchers examined samples from three other mammoths from the same area in northern Siberia, but only Yuka's contained significant long RNA molecules. This means that a combination of rare environmental luck and extreme preservation may lead to the future uncovering of similar ancient remains.
Another surprise emerged during the analysis of the genetic data. Although researchers had assumed for years that Yuka was a female, the updated tests clearly show that he was a male. The researchers confirmed this after comparing Yuka’s DNA samples with other samples from several laboratories. The finding upended existing knowledge about the evolution of mammoths and the interpretation of their external characteristics.
The broader implications of the findings
RNA is known to be the genetic component of many viruses, such as influenza and coronavirus. The researchers believe that in the future, it will be possible to identify ancient viruses that lived during the Ice Age using similar methods. No active RNA viruses have been found in the Yuka, but the possibility of discovering viruses with ancient genetic material is fascinating the scientific community.
While the discussion of reviving mammoths using genetic engineering technology has been making headlines in recent years, the researchers emphasize that the RNA molecules found will not impact de-extinction efforts.
The RNA found is related to muscle development, a process very similar to that which also occurs in their close relatives, the elephants. However, the discovery of such ancient RNA molecules is a milestone. In the future, it may finally be possible to understand how mammoth genes were activated during life or how the cold-regulation system that adapted them to the Arctic climate evolved.
To some researchers, the idea of finding RNA molecules in mammoth hair follicles is particularly tempting. Locating genes that were activated in the hair follicles could unlock the secret of the mammoths' thick fur and lead to furthering the science of developing similar characteristics in modern animals.