I have pointed to the fact that mtDNA genetics has suggested that the polar bear is actually a derived lineage of brown bears. And, more specifically, that some extant lineages of brown bears share a more recent common ancestor with polar bears than other brown bears. In other words, brown bears are paraphyletic. Apparently there has been dispute of when the polar bear morph emerged from the brown bears. Luckily polar bears have been resident in a region where the likelihood of preservation of ancient DNA is relatively high. PNAS has a new paper which reports on the extraction of genetic material from ancient polar bear remains. Complete mitochondrial genome of a Pleistocene jawbone unveils the origin of polar bear:
The polar bear has become the flagship species in the climate-change discussion. However, little is known about how past climate impacted its evolution and persistence, given an extremely poor fossil ...
