World study: if American, ancestors walked Bering land bridge

William Atkins
Wednesday, 28 November 2007 21:52

Science - Biology

Genetic data shows that about 12,000 years ago eastern Asian peoples walked over the Bering Strait land bridge that temporarily connected Siberia and North America.         

Other theories hold that humans used ocean waters to cross into North and South America from various shores around 30,000 years ago. This study may help to resolve the controversy as to when and where Native Americans first crossed over to the New World.

The Bering Strait land bridge was a land bridge about 1,000 miles (1,600 kilometers) in width that joined Alaska and eastern Siberia at various times during the Pleistocene ice ages, a period of time from about 1,8 million years to about 11,500 years ago.

The paper “Genetic Variation and Population Structure in Native Americans”, published November 23, 2007, appears in the online version of the journal PloS Genetics.

U.S. genetic researcher Noah A. Rosenberg, from the University of Michigan Medical School, and one of the authors, states, “We have reasonably clear genetic evidence that the most likely candidate for the source of Native American populations is somewhere in east Asia.” [Fox News]

To make these conclusions, the researchers examined genetic diversity and population structure taken from DNA (deoxyribonucleic acid) samples of fifty populations from around the world.

They looked at 422 individuals representing 24 Native American populations in North, Central, and South America, specifically, looking at 678 genetic markers from within that DNA.

They combined this data with similar data taken from 54 indigenous populations found outside of the Americas and scattered all over the world—five of these groups were from Native American groups.

The group made their conclusion based on evidence from two genetic factors between Siberian and American peoples. The first genetic factor shows that the similarity in genes between the two peoples becomes less distinct the further south the people migrated in the Americas. The second genetic factor shows a unique genetic mutation that is found only in Native American and Siberian ancestors.