The question whether Native Americans come to the Americas in just one wave of migration or in two migratory waves could not be answered yet with certitude by scientists and historians.
A new research conducted by a team of anthropologists and geneticists is challenging a centuries-old hypothesis about Native Americans' origins. In an article published on Tuesday in Science, the research team reports tracing Native Americans to a single group settled in America far later than what was previously thought.
The team of researchers studied sequenced genomes of Native American volunteers with heritage from Americas, Oceania, and Siberia, as well as sequenced DNA from ancient bones. According to a computational geneticist at the University of Berkeley California, Rasmus Nielsen, and one of the co-authors of the study, people with Athanbascan and Amerindian heritage were contacted by the researchers and asked to participate as volunteers in their study.
Athanbascan and Amerindians are the two ethnic derivations of Native Americans descent. The scientists studied their mitochondrial DNA (mDNA) passed from mother to child.
According to the report published in Science, the conclusions of this new research change fundamentally what scientists previously thought. What the team found contradicts theories that an earlier migration occurred from Europe, since Native Americans seem to have a common Siberian origin.
According to the results of their study, Rasmus and his colleagues propose a new migration timeline in which a single group separated from an East Asian population about 23,000 years ago. Coming from northeast Asia, the migratory group crossed the Bering Land Bridge between Alaska and northeast Asia. Their descendants have later spread to the rest of the Americas. Much recently than previous theories, about 13,000 years ago, Native Americans started to split into different groups. This created the cultural and genetic diversity we witness today.
Rasmus and his colleagues refute the previous theory that sustained the fact that people moved into Alaska 35,000 years ago. According to the results of their research the ancestors of modern Amerindians arrived much more recently, and the whole process happened relatively fast.
Rasmus' research team's theory also come in contradiction to another line of thought that believes more than 15,000 years ago two different populations have come from Siberia to the Americas.
David Reich, a professor at Harvard, declared for the New York Times that the results of this new study are "surprising", since the scientific community already gathered overwhelming evidence of two founding populations in the Americas. Reich's group sustains the theory of two migratory groups. According to them, one group can be considered as the First Americans, and the second group can be identified as Population Y, related to indigenous Andaman Islanders, New Guineans, and Australians.
Both groups of scientists agree, despite their differences, that Native Americans can trace their ancestry to Eurasian migrants having Australasian ancestry.
