![]() Still, the multiple samples of mitochondrial DNA would allow the researchers to expand and corroborate results gleaned from a nuclear genome, which is considered more reliable because it contains fewer mutations. These short, maternally inherited lengths of genetic code are easier to sequence but provide less information about ancestry than the much larger nuclear genome. ![]() While most of the cell’s DNA is contained in the nucleus, the mitochondria also has its own DNA. The team selected and sequenced the mitochondrial genomes of 14 samples that included a baby woolly rhino found mummified in the permafrost with much of its hide intact and from a scrap of rhino meat recovered from the stomach of an Ice Age puppy found with its internal organs intact.Īnimal cells contain both nuclear and mitochondrial DNA. They then screened those samples to find the ones with the most pristine genetic material. Finding samples meant scientists spent years tramping around the increasingly sodden Siberian permafrost to track down pieces of bone, tissue and hair from specimens. The ancient animal’s DNA would reveal how inbred or genetically diverse the woolly rhino was, which would allow researchers to infer when the population started shrinking before going extinct. To find out when that decline likely began, Dalen and his colleagues needed good quality samples of woolly rhino DNA. “Or 14,000 years ago when we know the planet went through a period of rapid warming?” “Did the decline start 30,000 years ago when humans appeared,” says Dalen. During this roughly 2,000-year period of warmth, the meltwater gushing from the planet’s immense ice sheets raised sea level by approximately 50 feet.įor the paper’s senior author Love Dalen, a paleogeneticist at Stockholm University and the Swedish Museum of Natural History, the goal was to establish when the woolly rhino’s population started to decline and what that lined up with. The animal’s last centuries of existence coincided with a sudden and severe warming event called the Bølling–Allerød interstadial, which began around 14,700 years ago. Humans are thought to have first made their way to the rhino’s Siberian stronghold around 30,000 years ago, meaning they overlapped with woolly rhinos for some 16,000 years. Scientists speculate that woolly rhinos used their horns, which are thinner and more blade-like than those of living rhinos, to sweep away snow and nibble at frost-crusted tufts of greenery.īut suddenly, around 14,000 years ago the woolly rhino died out. They were roughly the same size as the white rhinos of today, which can reach up to five tons. The woolly rhino was a fur-matted fortress of a creature that grazed across the dry, frigid steppe ecosystem of northern Eurasia, including modern-day France but particularly in Siberia, for hundreds of thousands of years. “But our findings highlight the role of rapid climate change in the woolly rhino’s extinction.” “Humans are well known to alter their environment and so the assumption is that if it was a large animal it would have been useful to people as food and that must have caused its demise,” says Edana Lord, a graduate student at the Centre for Palaeogentics and co-first author of the paper. Many researchers have proposed that the mammals were hunted into extinction by Homo sapiens in what’s been termed the “ overkill hypothesis.” Now, in research published today in Current Biology, scientists who analyzed the animal’s DNA suggest that it may have been the planet’s swiftly changing climate that undid the species. ![]() The explanation for the demise of Ice Age megafauna, including the woolly mammoth, giant sloth and saber-toothed cat, has been debated for decades. But were humans’ artistic renderings of the woolly rhino accompanied by hunting that drove the creatures extinct roughly 14,000 years ago? ![]() Some 30,000 years ago, the hulking woolly rhinoceros and its curved, three-foot-long horn inspired ancient humans to streak the limestone walls of Chauvet Cave in southern France with vivid charcoal portraits of the Ice Age beast.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |