"From this very limited data set we've been trying to draw conclusions on what went on in central Europe without even having bears in central Europe.
"When we get access to [ancient DNA samples] from a wider part of the historic distribution of brown bears, it's not surprising that we get different conclusions."
Götherström also reports that some central European bear fossils have recently been dated to the time of the height of the Ice Age#8212;adding evidence to the new theory.
The research appeared in the latest issue of Molecular Ecology.
Hunting Pressures
With Mother Nature off the hook, human hands may have played a greater role in shaping modern bear genetics, the authors suggest.
As Europe's wilderness areas were gradually settled, bears were hunted and eventually fragmented into the isolated populations that survive today.
Lisette Waits of the University of Idaho's Conservation and Ecological Genetics Lab, who was not involved in the study, called its results both "convincing and intriguing."
"The authors suggest that the current structure might be explained simply by genetic drift that occurred when populations were reduced in size and became isolated due to human pressures of habitat loss and hunting," she said.
Boosting Bear Populations
The findings could have conservation implications for today's populations of European brown bears—many of which are fighting for a foothold in a highly populated continent.
Waits noted that some previous mtDNA analyses had been used to argue against efforts to supplement small bear populations with animals from other groups, because doing so might mix distinct genetic groups.
But "this work suggests that the isolation is more recent [and] does not trace back to the [last Ice Age], so these results could open the door" for such policies.
Study co-author Cristina E. Valdiosera is from Madrid's Centro Mixto UCM-ISCIII de Evoluciòn and Comportamiento Humanos. Most of the research was completed in the laboratory, which is run by Juan Luis Arsuaga.
"A big debate in conservation genetics [concerns] if you can translocate bears from one population to another," she said.
"We need to do other studies, but if we had bear populations connected until recent times, there should not be a reason why we could not translocate bears into the populations in Italy or Spain that are in danger of extinction."
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