🇺🇸▼
In its last moments, Yuka, a woolly mammoth, may have been desperately trying to outrun a cave lion. This conclusion comes from scientists who have recently studied the genetic material recovered from the animal. Yuka's remains were preserved in permafrost, the permanently frozen ground of the Siberian tundra. The hind legs of the mummified mammoth bear scratches that tell a violent story. Furthermore, the muscle tissue exhibits molecular evidence of extreme stress. Molecules called RNA hint that the mammoth's muscles were exhausted from a desperate run to escape a predator. This genetic material represents the oldest RNA ever recovered from any animal. It also offers a rare and intimate peek into Yuka's life approximately 40,000 years ago.
Scientists shared these groundbreaking findings in the January 8 issue of the journal Cell. Until now, the oldest RNA that biologists have successfully decoded was about 14,000 years old. That previous record holder came from a wolf. The new sample from Yuka shows that RNA may persist far longer than scientists had previously suspected. This discovery fundamentally changes our understanding of how long genetic traces can survive in the natural world. RNA has long been considered DNA's more delicate cousin. Standard textbooks suggest that RNA degrades almost immediately after an organism dies. Because of this fragility, researchers who have studied Ice Age animals at a molecular level have tended to focus on DNA rather than RNA. "I think people just assumed that it wouldn't work for RNA, so they haven't tried," says Love Dalén. He is a biologist at Stockholm University in Sweden. Dalén explains that the scientific community largely overlooked RNA because the consensus was that it would disintegrate too quickly to be useful for study.
But the freezing environment that mummified Yuka's remains proved perfect for preserving its RNA. The permafrost acted as a natural freezer, halting the chemical processes that usually destroy genetic material. This unique condition allowed the RNA to survive for millennia, waiting to be discovered by modern science. The study of these ancient molecules opens a new chapter in paleogenetics, allowing scientists to move beyond static DNA to the dynamic processes of life.
DNA contains the full genetic instructions for how to build an animal. It holds the blueprint for every trait, ranging from the length of the trunk to the thickness of the fur. RNA is the building manager. It reads the instructions from the DNA and tells cells exactly what to build and when to build it. Without RNA, the plans in the DNA would remain unfulfilled. Looking at RNA gives scientists a snapshot of a cell's activity at a particular time. It shows which genes were switched on or off during the animal's final hours. This information allows researchers to reconstruct the biological state of the creature. It can tell them about the tissue the cell was in and the specific physiological events occurring. It even can reveal an animal's health, stress levels, and physical condition at the moment of death.
Dalén and his colleagues analyzed RNA samples from 10 woolly mammoths. The tissue had long lay frozen in the Siberian permafrost, preserved in a time capsule of ice. Yuka's RNA was preserved well enough for the team to uncover new biological details that were previously impossible to access. Among the most significant findings was evidence of cellular stress. The molecules indicated that the cells were reacting to extreme physical exertion, supporting the theory that Yuka was running for his life.