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Tuesday, 26 October 2010

PBS documentary sites evidence for Solutrean Hypothesis

Left: MitochondrialDNA (mtDNA) haplogroup testing led to the surprising hypothesis that some of the first Americans came from Europe thousands of years ago.




From Scientific American Frontiers

The conventional wisdom to explain the peopling of the Americas is that migrants crossed from northeast Asia to Alaska around 13,000 years ago to become the ancestors of today's Native Americans. But mtDNA analysis has revealed some unexpected links between Europe and North America. When scientists analyzed the mtDNA of a broad sample of living Native Americans, they found that about 97 percent had mtDNA from haplogroups A, B, C or D. These haplogroups are all present in modern day Siberia and Asia, so it makes sense that the forefathers of those Native Americans came from those regions. But the surprise was that about 3 percent of the Native Americans tested had mtDNA from a different haplogroup, called X. Some populations, such as the Ojibwa from the Great Lakes region, have a high concentration of X - 25 percent.

How did haplogroup X get to North America? Some X has been found in Mongolia, but it's definitely not common in modern Asia. It can, however, be found in about 4 percent of the present day European population. Genetic anthropologists suggest that the presence of X in North America points to an early migration westward from Europe. By looking at the various mutations within haplogroup X, scientists are able to use that "genetic clock" to estimate when those early Europeans would have arrived. Depending on how large a group they assume headed west, they come up with two time ranges - either between 36,000 and 23,000 years ago or between 17,000 and 12,000 years ago.

X definitely did not arrive in America with the European explorers of the last 500 years or so. European X and American X are different enough that scientists say they must have diverged thousands of years ago, long before the age of exploration introduced European genes to the New World. Scientists have also done some testing on pre-Columbian Native American skeletal remains from before 1300, and found haplogroup X in the same proportion it's present in modern Native American populations. Read more



Hat tip solutrean liberation front

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