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Popular Archaeology Penn study results strengthen the theory that at least some of the earliest Native Americans may have found their way into the Americas across the ancient Bering Land Bridge from Siberia. Ancestors of the earliest Native Americans may indeed be traced to Asia, according to a recent genetic study conducted by the University of Pennsylvania and the Institute of Cytology and Genetics in Novosibirsk, Russia. The researchers, led by Theodore Schurr, an associate professor in Penn's Department of Anthropology, in collaboration with Ludmila Osipova of the Institute, suggest that an ancient people living in a mountainous region in southern Siberia may have been the genetic source for those who migrated westward, possibly crossing the Bering Land Bridge to become the earliest Native Americans. Known as the Altai region, it is located at the four corners of what is today China, Russia, Mongolia, and Kazakhstan. Says Schurr, it "is a key area because it's a place that people have been coming and going for thousands and thousands of years. Our goal in working in this area was to better define what those founding lineages or sister lineages are to Native American populations." The team analyzed the genetics of individuals living in Russia's Altai Republic for markers in both mitochondrial DNA and Y chromosome DNA. Mitochondrial DNA traces the maternal, or female line of descent, whereas Y chromosome DNA traces the paternal, or male, descent. They compared the samples to those that had previously been collected from individuals in southern Siberia, East Asia, Central Asia, Mongolia, and a number of different Native American groups. After analyzing the Y chromosome DNA, the researchers found a unique mutation common to both the Native Americans and southern Altaians in a lineage dubbed as "Q". They found similar results when analyzing the mitochondrial DNA. "We find forms of haplogroups C and D in southern Altaians and D in northern Altaians that look like some of the founder types that arose in North America, although the northern Altaians appeared more distantly related to Native Americans" says Schurr. Determining how long ago the mutations took place, the researchers concluded that the southern Altaian lineage diverged genetically from the Native American lineage about 13,000 to 14,000 years ago. This correlates with current theories that support the migration of peoples into the Americas from Siberia between roughly 15,000 and 20,000 years ago. The large and diverse nature of the database ensured a relatively high degree of confidence among the researchers about the validity and precision of the findings. Says Schurr, "at this level of resolution we can see the connections more clearly". In addition to Schurr and Doctoral Student Matthew Dulik, the research was conducted by Sergey Zhadanov, Ayken Askapuli, Lydia Gau, Omer Gokcumen and Samara Rubinstein of Penn's Department of Anthropology. The research was supported by the University of Pennsylvania, the National Science Foundation, the Social Sciences and Humanities Research Council of Canada and the Russian Basic Fund for Research. The National Geographic Society also provided infrastructural support to the Schurr lab. The detailed study is published in the American Journal of Human Genetics.
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