Polar bears diverged from brown bears surprisingly recently — within the past 500,000 years, researchers report today in Cell1. Previous studies suggested that the separation occurred between 600,000 and 5 million years ago.
The latest analysis compares the complete nuclear genomes of 79 polar bears from Greenland with those of 10 brown bears from a variety of locations: Sweden, Finland, Montana and three islands off the coast of Alaska, Admiralty, Baranof and Chichagof.
It finds that the two species diverged between 479,000 and 343,000 years ago, which would make the polar bear “remarkably younger” than most scientists thought, says Rasmus Nielsen, a computational biologist at the University of California, Berkeley, who worked on the study.
Read the full, original story: Genome reveals polar bear’s youth