Two Distinct Wooly Mammoth Groups Discovered

Scientists, lead by Stephan C. Schuster of Penn State University, extracted DNA from frozen mammoth hair samples found throughout a large swath of northern Siberia, in an attempt to paint a new picture of the ancient and long lost animals. What they found was that, unlike previously believed, there were two distinct groups of the mammoths, or “clades”.

"The population was split into two groups, then one of the groups died out 45,000 years ago, long before the first humans began to appear in the region," said Schuster. The team also found that individual wooly mammoths seem to have been relatively closely related to one another, having a very low genetic diversity.

"This low genetic divergence is surprising because the woolly mammoth had an extraordinarily wide range: from Western Europe, to the Bering Strait in Siberia, to North America," said another Penn State team member Webb Miller. He went on to add that this low genetic diversity "may have degraded the biological fitness of these animals in a time of changing environments and other challenges."

Schuster notes that this low genetic diversity is also apparent in Asian elephants now living in southern India. Many have speculated that this low genetic diversity is hindering efforts to maintain and increase the population of elephants.

To be published in the June 9 issue of the journal Proceedings of the National Academy of Sciences, the researchers make note that the smaller clade appears to have died out long before the larger clade. They suspect that the relatively small range in genetic diversity throughout their population may have left them vulnerable to a sudden and unexpected change in the environment.

"This discovery is particularly interesting because it rules out human hunting as a contributing factor, leaving climate change and disease as the most probably causes of extinction," Schuster said.

Posted by Josh Hill.

http://www.livescience.com/animals/080609-woolly-mammoth.html