(ORDO NEWS) — The history of the formation of polar and brown bears largely coincides with the history of the development of relations between different branches of humanity.
This is reported in a study by American and Finnish scientists, writes Proceedings of the National Academy of Sciences.
“The history of polar and brown bears is a fairly accurate analog of human evolution. Scientists once thought that humans and Neanderthals simply split into two separate species.
But the decoding of ancient genomes showed that representatives of the archaic branches of humanity interbred with the ancestors of modern people.
Polar and brown bears are another system where this has happened,” said study lead author Charlotte Lindquist, an assistant professor of biological sciences at the University of Buffalo College of Arts and Sciences and an expert in bear genetics.
Researchers have deciphered the genome of a polar bear that lived about 115-130 thousand years ago on the Svalbard archipelago.
The predator’s DNA was extracted from a tooth attached to a subfossil (not fully fossilized) jaw bone, stored at the Natural History Museum in Oslo.
In addition, the genomes of 64 modern polar and brown bears were studied, including several new genomes from Alaska.
The data collected by scientists made it possible to calculate that polar and brown bears became separate species from 1.3 to 1.6 million years ago.
After separation, the polar bears experienced a long period of genetic bottleneck. This has resulted in brown bears now having significantly higher levels of genetic diversity.
In modern conditions, against the backdrop of shrinking Arctic ice, polar and brown bears may be more common in places where their ranges overlap, making their shared evolutionary history particularly interesting, Lindqvist noted.
The two species are capable of interbreeding – recently hybrids of grizzlies and polar bears have been seen in North America.
According to some scientists, this leads to the blurring of the genome of polar bears and may lead to the disappearance of the largest land predator on the planet.
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