Sunday, November 25, 2007

Bear hunting altered genetics more than Ice Age isolation
Twenty thousand years ago Europe was covered by ice down to Germany, and the climate in the rest of Europe was such that several species were confined to the southern regions, like the Iberian Peninsula and Italy. These regions were refuges, areas where species could survive during cold periods and then re-colonize central and northern Europe when it got warmer. But the brown bear was not limited to these regions­it could roam freely across major parts of southern and central Europe. The current study analyzed mitochondria from bear remains. Some of the fossils are 20,000 years old. The analysis shows that the genetic pattern in these ancient brown bears differed from that of bears living today.

“Previously today’s genetic structure was interpreted as showing that the brown bear was isolated in southern Europe, just like many other species. But our study shows that this was not the case,” says Love DalĂ©n, one of the Swedes participating in the study.

The new findings show instead that the brown bear survived in central Europe, even during the coldest period of the Ice Age. The scientists now believe that the genetic pattern found in today’s brown bears is the result of historical hunting and of human activities in the brown bear’s natural environment. A few thousand years ago, there were brown bears all over Europe, while today there are just a few remaining populations in Spain, Italy, the Balkans, and Scandinavia.