From the Ears of Cave Bears

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Yeah, it's a click-bait title, but at least it doesn't misrepresent or editorialize. 

An article about investigating the genomic evidence of the evolution of cave bears.

"We sequenced the cave bear genome using a 360,000-year-old ear bone and had to rewrite their evolutionary history" | The Conversation

Cave bears were giant plant eating bears that roamed Europe and northern Asia, and went extinct around 25 thousand years ago. They hibernated in caves during the winter. This was a dangerous time, as those which had failed to fatten up enough during the summer would not survive hibernation.

As a result, many caves across Europe and northern Asia are now filled with the bones of cave bears, each one containing potentially thousands of individuals. In our new study, we analysed a bone from a cave in the Caucasus Mountains.

Our team recovered the genome from a 360,000-year-old cave bear, revealing new details of the animals' evolutionary history and almost rewriting their entire evolutionary tree. As well as what it can tell us about cave bear evolution, this discovery is a breakthrough for the field of ancient DNA.

February 2021 was an important month for the study of palaeogenomes – the analysis of genomes from extinct species. Two studies were published just one day apart, one reporting the oldest genome from a permafrost environment – from a 1.2 million year old mammoth tooth – and our new research, reporting the oldest genome from a non-permafrost environment.

[. . .]

[A] recent discovery in the field of ancient DNA has changed things. A particular bone in the mammalian skeleton – the petrous bone, part of the skull which contains the inner ear – seems to be more resistant to contamination from the external environment, potentially due to its extremely high density. In our previous studies we used petrous bones to sequence the genomes of much younger extinct cave bears. Some of these have contained as much a 70% cave bear DNA.

We wondered if this was the way to recover even older palaeogenomes. So we selected a cave bear petrous bone dating to 360,000 years ago, within the geological period known as the Middle Pleistocene, and took it to the lab.

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Yeah, it's a click-bait title...

[Tank]

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Nicked and posted elsewhere.