One of the last woolly rhinos to walk Earth was eaten by a wolf pup — and scientists have now sequenced its genome from the undigested meat
Scientists analyzed the genome of a 14,400-year-old woolly rhino from a piece of flesh found in the stomach of an ancient baby wolf. The findings give experts insight into the extinction of the woolly rhino, which likely occurred quickly due to climate change.
The woolly rhinoceros (Coelodonta antiquitatis) tissue was found inside the mummified remains of a wolf pup, initially discovered in Siberian permafrost in 2011. A subsequent necropsy of the puppy revealed his last meal: He dined on one of Earth’s last woolly rhinos. But now scientists have figured out how to sequence the animal’s entire genome from pieces of undigested rhino flesh.
“Complete genome sequencing of an Ice Age animal found in the stomach of another animal has never been done before,” Camilo Chacón-Duquebioinformatician at Uppsala University in Sweden and co-author of the new study, said in a statement.
In the new research, published Wednesday January 14 in the journal Genome biology and evolutionResearchers analyzed the rhino’s woolly muscle tissue and compared it to older examples to study the species’ population size and level of inbreeding just before its extinction. This piece of meat provided unprecedented information about the disappearance of the woolly rhino.
Many endangered species leave clues of their decline in their geographic range, population size, and genome. As an animal’s populations decline, they may become concentrated in a particular area. For example, woolly mammoths (Mammuthus primigenius) persisted until about 4,000 years ago on a remote island in Siberia. But their small population contributed to inbreeding, and this lack of genetic diversity may have ultimately doomed the mammoth. (Although another study suggests that these island mammoths died in a random mystery event.)
The woolly rhino, however, was widespread in northern Eurasia until about 35,000 years ago. Its geographic range shrank over time and the species concentrated in northeastern Siberia, before disappearing around 14,000 years ago. The piece of woolly rhino tissue discovered in the cub’s stomach has been carbon dated to 14,400 years ago, meaning the woolly rhino was likely one of the last of its species.
The researchers generated the woolly rhino genome from preserved muscle tissue and compared it to two older genomes dated 18,000 and 49,000 years ago. They found that the three rhinos had similar levels of inbreeding and genetic diversity, suggesting that there was a relatively stable woolly rhino population in northern Siberia until at least 14,400 years ago, and that their extinction must have occurred rapidly thereafter.
“Our results show that woolly rhinos had a viable population for 15,000 years after the first humans arrived in northeastern Siberia, suggesting that global warming, rather than human hunting, caused the extinction,” co-author of the study. I love Dalénprofessor of evolutionary genomics at the Center for Paleogenetics in Sweden, said in the release. The results build on previous work by many of the same researchers.
Rapid changes in global climate occurred near the end of the Pleistocene Epoch (the last ice age) and many large mammals disappeared. The disappearance of the woolly rhino aligns with a period called the Bølling-Allerød interstadial, which involved an abrupt warming of the Northern Hemisphere climate around 14,700 to 12,900 years ago. This considerably warmer climate may have wiped out the preferred foods of cold-adapted herbivorous woolly rhinos and thus contributed to their rapid decline.
Even if the new genome does not solve all the mysteries surrounding the extinction of the woolly rhino, researchers have demonstrated that it is possible to recover the DNA of one animal inside another.
“It was really exciting, but also very challenging, to extract a complete genome from such an unusual sample,” said the study’s lead author, Sólveig Guðjónsdóttir, a researcher at Stockholm University, in the release.
The researchers hope their achievements will pave the way for future DNA and genomic analyzes of animal tissues from “unlikely sources”.
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