Scientists have discovered distant DNA links between Aboriginal Australians and tribes living deep within the Brazilian Amazon rainforest. Two different groups of researchers who conducted genetic analyses established that people sharing DNA links with indigenous Australians cross the Bering land bridge between Siberia and the Americas thousands of years ago.
One study led by David Reich of Harvard University was published in the journal Nature. David Reich and his colleagues concluded that there could have been multiple migrations from Siberia to the Americas. They said the first migration from Siberia that occurred about 15,000 years ago consisted of two different groups: the First Americans and Population Y. Researchers said the Population Y could have arrived before, after or around the same time as First Americans.
David Reich concluded that Population Y “carried ancestry more closely related to indigenous Australians, New Guineans and Andaman Islanders than to any present-day Eurasians or Native Americans.” The term ‘Population Y’ is derived from Ypykuéra, which means ancestor in the Tupi language spoken by two Amazonian tribes, the Karitiana and Surui.
These tribes show strong connections to Australasians. However, Reich stressed that there was no “unmixed population” related to Australasians that came to the Americas. He said the Population Y contributed Australasian genes to the Amazonian tribes. This group was mixed with a Native American lineage by the time it reached the Amazon. Harvard scientists said about 85% ancestry in Amazonian tribes came from the Population Y, while just 1-2% came from Australasians.
Danish group disagrees on the source of ancestry
Another study conducted by researchers at the University of Copenhagen was published in the Science magazine. Danish scientists also found links between Australasian DNA and that of Amazonian tribes. However, this study argues that the Australasian DNA came to the Americas 9,000 years ago rather than 15,000 years claimed by the Harvard study.
The Danish study concluded that Australasian DNA reached the Americas via Aleutian Islanders, who also carried DNA characteristics of Aboriginal Australians.