100,000-Year-Old Polar Bear Genome Reveals Ancient Hybridization With Brown Bears
Published:23 Jun.2022 Source:University of California - Santa Cruz
The study, led by scientists at the University of California, Santa Cruz, was published June 16 in Nature Ecology & Evolution. The researchers obtained ancient DNA from the skull of a juvenile polar bear that was found in 2009 on the coast of the Beaufort Sea in Arctic Alaska. Scientists nicknamed the bear 'Bruno,' although DNA analysis later showed it to be a female.
"The availability of Bruno's paleogenome has made it possible to detect an ancient admixture event that impacted all living brown bears," said first author Ming-Shan Wang, a postdoctoral scientist in the UCSC Paleogenomics Lab. Corresponding author Beth Shapiro, professor of ecology and evolutionary biology at UC Santa Cruz and an investigator at the Howard Hughes Medical Institute, said the team's genomic analyses show that Bruno belonged to a polar bear population that was ancestral to living polar bears. At some point, probably after around 125,000 years ago, she said, the polar bear lineage leading to Bruno and the brown bear lineage leading to all living brown bears crossed paths and hybridized.