DNA from 92 pre-Columbian people, including a well-preserved mummy of a girl who was sacrificed 500 years ago, shed light on who the first Native Americans were, what their initial migration path was, and what might have happened to certain early indigenous populations after Europeans arrived in the Americas.
The research, published in the journal Science Advances, represents the first large-scale study of ancient DNA from early Americans.
The findings suggest that people from Siberia were isolated for around 2400-9000 years in what is now the Bering Land Bridge region (referred to as "Beringia" and including parts of Russia and Alaska) before entering North America 16,000 years ago. They traveled down the Pacific coastline, with some reaching southern Chile 14,600 years ago.
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One of the descendants of these first Native Americans was "La Doncella," The Maiden, a 13-year-old girl who died during a ritual sacrifice at Mount Llullaillaco, Argentina, 500 years ago. Her frozen body, discovered in 1999, was hailed as being one of the best-preserved mummies ever found.
Bastien Llamas, a senior research associate with the University of Adelaide's Australian Center for Ancient DNA (ACAD), told Discovery News that "it seems that her mitochondrial lineage did not survive until today, and that this pattern is not unusual."
Mitochondrial DNA represents maternal genetic lineages. It was the focus of the new study. The fact that such DNA for La Doncella has not yet been found in existing Native Americans suggests that she has no direct living relatives. The researchers also could not make a modern match with the other 91 analyzed pre-Columbian remains.
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Llamas said, "The fact that none of the 92 pre-Columbian mitochondrial lineages survived to today is due to a combination of factors: 1- indigenous populations were fragmented and groups lived isolated from each other; 2- some of these isolated groups became extinct following European contact; 3- many modern genetic lineages have not been surveyed yet."
It is known that many early Native Americans succumbed to diseases brought over by Europeans for which many had evolved no immunity. Such illnesses included syphilis, smallpox, measles, mumps, and the bubonic plague.
Nevertheless, Alan Cooper, who is the director of ACAD, suspects that at least some of the ancient genetic lineages did survive to modern times and will eventually be found in current populations, once enough individuals are analyzed.