New discoveries in Polar Bear genetics raise questions as to their origins.

Polar Bears have become an almost universal symbol for global warming. Some find them cute, others vicious, but no one can dispute their role in environmental issues. They are also famous for the  grizzly-polar bear hybrids found both in the wild and in captivity. For a long time now scientists have considered the polar bear a relatively new species that diverged from brown bears around 150,000 years ago. But, as this article shows, that might not be entirely true. Instead from samples of brown, black, and polar bear DNA scientist now believe that polar bears diverged from a common ancestor about 600,000 years ago.

Unlike other studies that have focused on mitochondrial DNA that is only inherited through the mother, this study focused on fourteen stretches of nuclear DNA to come to their conclusion. The effects of this study are questionable. It shows that bears did not evolve as quickly as once thought and may be more susceptible to environmental changes. It also showed previous times of bottlenecks in the species where DNA diversity quickly declined.

Other studies pinpoint interbreeding between small populations of bears in times of warming when populations dropped and diversity decreased. All of these studies highlight just how little we know about ursid evolution and genetics.