Extinct Cave Bear DNA Traces Discovered In Modern-Day Brown Bears, Proving Interbreeding

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For more than a hundred thousand years, cave bears lived on Earth, before they vanished about 24,000 years ago due to ancient humans and natural climate change of those times. Now, a new study revealed an exciting fact. Namely, the extinct cave bear DNA “lives” in modern-day brown bears.

The study, issued yesterday in the Nature Ecology And Evolution journal, is the first one to show that the DNA of an ancient ice-age animal left traces in the genome of a living relative. On the other hand, a previous study also showed the same thing in humans who present Neanderthal genes in between 1.5 – 4 percent of the total genome.

However, the modern-day bears only show up to 2.4% DNA traces inherited from the extinct cave bear species.

“By any standard definition, cave bears are extinct, but it doesn’t mean that their gene pool is erased, because they continue to live on in the genomes of these living animals,” said Axel Barlow, one of the study’s authors.

Modern-day brown bears inherited a part of the extinct cave bear DNA

The research also strengthens, once again, the theory that ancient species interbred. Examples of combinations between yaks and  Tibetan cows, as well as between brown bears and polar bears, are still prevalent today, millions of years after their common ancestors also coupled. The same happened with the ancient humans, as the researchers found a fossilized young girl of a Neanderthal mother and a Denisovan father.

Trying to determine why caver bears went extinct, the researchers analyzed a cave bear DNA sample extracted from ear bones of some of the specimens that lived 35,000 years ago. Then, by comparing that DNA with samples of brown bear and polar bear. While the latter two are surely relatives, the extinct cave bear DNA showed more similarities to the genome of brown bears, while no match was found with that of polar bears.

“If we get an overabundance of genome positions where cave bears and brown bears are showing more similarity to each other than to polar bears, then something else must have happened. And that something is the hybridization between the two species,” said Barlow who also added that this new study proved interbreeding in ancient animals, besides revealing that extinct cave bear DNA is still “alive” in modern-day brown bears.

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Jasmine holds a Master’s in Journalism from Ryerson University in Toronto and writes professionally in a broad variety of genres. She has worked as a senior manager in public relations and communications for major telecommunication companies, and is the former Deputy Director for Media Relations with the Modern Coalition. Jasmine writes primarily in our LGBTTQQIAAP and Science section.


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