Researchers at the Swedish Center for Paleogenetics have managed to analyze DNA from an extinct woolly rhinoceros – which was found in the stomach of a frozen prehistoric wolf pup.
– It is the first time ever that the genome of an animal – which was found inside another animal – from the Ice Age has been mapped, says Love Dalén, one of the researchers.
The find provides new clues about how the Ice Age rhinoceros became extinct.
One hundred thousand years ago, imposing rhinoceros roamed Europe and northern Asia. Three meters long, with two massive horns on their noses and a substantial coat, they were well equipped for the harsh climate.
– They also had substantial fat deposits. But what makes them a bit special compared to all rhinoceroses alive today is that they had a front horn that looked more like a saber, i.e. very flattened, and could be around two meters long, says Love Dalén, biologist and professor of evolutionary genetics at Stockholm University.
14,400 years ago they were only found in parts of Siberia. One of these woolly rhinos then ended up in the stomach of a wolf pup in Yakutia. It was just as bad for the puppy, who probably died in a landslide soon after the meal and froze in the permafrost where it was preserved until the present day.
“Push the boundaries”
Doing a complete analysis of prehistoric DNA is difficult as it is. Also, succeeding with tissue found in a stomach – whose job is to break down the meat – makes it even more complicated. According to the researchers, it has never been done before and the breakthrough has also been noticed by CNN.
– We were very lucky, because it had barely started to melt at all, says Camilo Chacón-Duque, another of the researchers.
What still made it worth trying is that the find is so young. The last woolly rhinoceros is thought to have died out 14,000 years ago, just 400 years later. Therefore, the DNA can provide clues about how the species was just before extinction.
– And we wanted to push the limits of what you can do with unusual, challenging samples like this, says Chacón-Duque.
When he and his colleague inserted the knife into the piece of meat in the laboratory, they knew from previous studies that it belonged to a rhinoceros.
– It’s very exciting and very scary because you don’t want to damage the sample by contaminating it. You also feel privileged to hold something that has been preserved for more than 14,000 years. It is an honor.
Climate change became the case
The researchers succeeded, and were able to compare with DNA from older rhinos (18,000 and 49,000 years old, respectively). The recent find showed no signs of inbreeding, which is a sign that there were probably many rhinos until they suddenly disappeared. It is therefore likely that it was not man who, for example, hunted the animals to death. So what did they die of? The clues point to another executioner – climate change as the ice age gave way, although other options cannot be ruled out.
– They were well adapted to the cold and a certain kind of landscape. When the landscapes changed, it may have put a lot of pressure on them, he says.
