Ancient DNA analysis, unexpected insights about peoples of Central, South America

The findings include two previously reported North and South America, one of which represents a continent-wide population turnover.

Clovis culture, the first widespread archaeological culture of North America, had a major demographic impact.

The authors analyzed genome-wide data from 49 individuals from Central and South America, some as old as 11,000 years ago. Previously, the only genomes that have been reported to be of sufficient quality to be less than 1,000 years old.

By Comparing Ancient and Modern Genomes from the Americas and other parts of the globe, the researchers were able to obtain qualitative insights into the early history of Central and South America.

Published in the newspaper Cell, the study was led by researchers at Harvard Medical School; the Howard Hughes Medical Institute; the Max Planck Institute for the Science of Human History; the University of California, Santa Cruz; Pennsylvania State University; the University of New Mexico; the University of São Paulo and other institutions in Argentina, Australia, Belize, Brazil, Chile, the European Union, Peru and the United States.

The researchers obtained official responsibility for the excavation and conduct of the analysis of human resources.

Clovis in Central America and South Americans

A distinctive DNA type associated with Clovis culture was found in Chile, Brazil and Belize 11,000 to 9,000 years ago.

12 years ago Chilean, Brazilian and Belizean Individuals, "said co-lead author Cosimo Posth of the Max Planck Institute for Science of Human History. "This supports the expansion of people who spread the Clovis culture in North America also reached Central and South America."

However, the clovis culture-associated lineage is missing in present-day South Americans and in ancient samples that are less than 9,000 years old.

"This is our second key discovery," said co-senior author David Reich, professor of genetics at Harvard Medical School and a Howard Hughes Medical Institute investigator. "We have shown that there was a continent-wide population replacement that began at least 9,000 years ago."

After the population replacement, there was a lot of genetic variation between old and new South American regions. This contrasts with West Eurasia and Africa, where there are few places with such long-standing continuity.

<a rel = "lightbox" href = "https://3c1703fe8d.site.internapcdn.net/newman/gfx/news/2018/ancientdnaev.jpg" title = "This visual abstract depicts the findings of Posth et al., who led a large-scale analysis of ancient genomes from Central and South America, and compared with other countries in the Americas. Credit: Posth et al./Cell">

California Channel Island-associated ancestry in the Andes

The latter previously unknown spread of people in the United States revealed that they had a distinctive history in the past few years.

The researchers say this is unlikely to reflect population spread especially from the Channel Islands into South America. Instead, they hypothesize that the connection between these regions is the result of expansions of people, and that such ancestry becomes more widespread in the Andes after South America.

"Said Nathan Nakatsuka, a research assistant in the Reich lab at Harvard Medical School and co-lead author of the United States. study. "There is archaeological evidence that the population in the Central Andes area greatly expanded after around 5,000 years ago." Spreads of particular subgroups during these events may be why we detect this ancestry afterward. "

The promise of ancient DNA research in the Americas

The researchers emphasize that their study gives a glimpse of the discoveries that may come through future work.

To learn about the initial movements of people in Central and South America, they say, it would be necessary to obtain a few years ago.

Even for this period between 11,000 and 3,000 years ago that this study is focused on, the picture is far from complete.

"We lacked ancient data from Amazonia, northern South America, and the Caribbean," said Reich. "Filling in these gaps should be a priority for future work."

"We are excited about the potential of research in this area," said co-senior author Johannes Krause of the Max Planck Institute for the Science of Human History. "With future regionally-focused studies with large sample sizes, we could realize the potential of ancient DNA to reveal the human diversity of this region."

Explore further:
First peoples: Study finds two ancient ancestries 'reconverged' with settling of South America

More information:
Cell, Posth et al .: "Reconstructing the Deep Population History of Central and South America" ​​DOI: 10.1016 / j.cell.2018.10.027, https://www.cell.com/cell/fulltext/S0092-8674(18 ) 31380-1