Scientists from the Centre for Palaeogenetics have successfully analyzed the genome of a 14,400-year-old Woolly Rhinoceros using remains retrieved from the stomach of an Ice Age wolf.
The analysis showed that the species remained genetically intact right up to the end of the last Ice Age, suggesting it went extinct due to a rapid population collapse rather than a prolonged demographic decline.
Ice Age Wolf’s Prey Identified as a Woolly Rhinoceros
According to a statement announcing the unusual recovery of Woolly Rhino DNA, the Ice Age wolf carrying the extinct animal’s remains was originally discovered in the north-eastern Siberian permafrost near the village of Tumat. When scientists performed an autopsy on the wolf’s remains, they discovered a small fragment of preserved animal tissue in the creature’s stomach.
Although initial radiocarbon tests placed the date of the wolf’s ‘woolly’ meal to roughly 14,400 years ago, genetically identifying the prey from this small sample that was also old and degraded was considered extremely difficult. Further complicating the task was the presence of the wolf’s DNA.
Sólveig Guðjónsdóttir, the study’s lead author, who carried out the work as part of her master’s thesis at Stockholm University, described attempting to extract the ancient DNA from such an “unusual sample” as both exciting and challenging.
“Sequencing the entire genome of an Ice Age animal found in the stomach of another animal has never been done before,” added Camilo Chacón-Duque, until recently a researcher at the Centre for Palaeogenetics and the study’s last author.
Species Maintained Surprising Genetic Stability as it Neared Extinction
Although difficult, the team ultimately extracted enough DNA to identify the wolf’s prey. According to the sequenced portion, the material belonged to the species Coelodonta antiquitatis, commonly known as the woolly rhinoceros. Combined with the radiocarbon dating, the test made the woolly mammoth specimen one of the youngest ever discovered, having perished extremely close to the end of the last Ice Age.
After sequencing the extinct animal’s DNA, the researchers compared it with two other high-quality woolly mammoth samples from 18,000 and 49,000 years ago. Due to the wide date range, the team used this analysis to search for signs of diminished genetic diversity and inbreeding, and track the species’ long-term changes to the number of potentially harmful genetic mutations.
When the research team ran the genomic comparisons, they found no signs of genetic deterioration. They also saw no signs in the genome suggesting a long-term population decline.
“Our analyses showed a surprisingly stable genetic pattern with no change in inbreeding levels through tens of thousands of years prior to the extinction of woolly rhinos,” explained Edana Lord, formerly a postdoctoral researcher at the Centre for Palaeogenetics.
Given the proximity between the new sample and the species’ ultimate extinction, they believe this result suggests that woolly rhinos maintained a “stable and relatively large population unit” up until it disappeared from the fossil record.
Potential Link to Global Warming and the Implications for Species Conservation
In the authors’ conclusion, they suggest the woolly mammoth’s extinction occurred quickly compared to other species that show a slow, gradual decline in genetic diversity before dying out. Although more work is needed to identify the cause of this rapid decline, the team suggests that global warming may have been a critical factor.
“Our results show that the woolly rhinos had a viable population for 15,000 years after the first humans arrived in northeastern Siberia, which suggests that climate warming rather than human hunting caused the extinction,” explained Love Dalén, professor of evolutionary genomics at the Centre for Palaeogenetics.
When discussing the implications of their research and methods, Professor Dalén said that recovering DNA from an individual rhinoceros that lived just before the species’ extinction is “challenging.” However, the study author also said this type of research may provide insight into the event or events that caused the ultimate extinction, “which may also be relevant for the conservation of endangered species today.”
The study “Genome shows no recent inbreeding in near-extinction woolly rhinoceros sample found in ancient wolf’s stomach” was published in Genome Biology and Evolution. The Centre for Palaeogenetics is a collaboration between Stockholm University and the Swedish Museum of Natural History.
Christopher Plain is a Science Fiction and Fantasy novelist and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him directly at christopher@thedebrief.org.