Female ancester of all living polar bears was a brown bear

According to an article from Biology News. Net, an international team of scientits has discovered that the female ancestor of all living polar bears was a brown bear that lived in the vicinity of present-day Britain and Ireland just prior to the peak of the last ice age -- 20,000 to 50,000 years ago. Beth Shapiro, the shaffer Associate Professor of Biology at Penn State Unibersity and one of the team's leaders, explained that climate changes affecting the North Atlantic ice sheet probably gave rise to periodic overlaps in bear habitats. These overlaps then led to hybridization, or interbreading -- and event that caused maternal DNA from brown bears to be introduced into polar bears.

Polar bears are being driven to extinxtion as increasing temperatures are devastating their habitat, melting away the Arctic ice the need to survive and causing the seals that polar bears hunt for food to become increasingly scarce. So a thorough understanding of the polar bear's deep genetic history and its response to previous environmental changes could help to inform conservation strategies for the dwindling polupation of polar bears today. Shapiro said that a more complete investigation of this part of the genetic story could answer deeper questions about how interactions with other species and environment changes affected the polar bear in the distant past, how frequently hybridizations between species actually happened, and how htese hybrizations affexted the genetic diversity of bear generally.