The international team of researchers has uncovered unexpected details about the human population of Central and South America by studying the first high-quality ancient DNA data from these regions.
Findings include two previously unknown genetic exchanges between North and South America, one of which is traffic across the continent.
The results suggest that people who spread Clovis culture, the first widespread archaeological culture of North America, had a significant demographic impact in the south than previously appreciated.
The authors analyzed gene data from 49 individuals from Central and South America, some older than 11,000 years old. Previously, the only genes that were reported from the region and who provided enough quality data for analysis were older than 1,000 years.
By comparing ancient and modern genomes from America and other parts of the world, researchers were able to gain qualitatively new knowledge about the early history of Central and South America.
Published in the magazine Cell, the study was conducted by researchers at the Harvard Medical School; Hovard Hughes Medical Institute; Mak Planck Institute for the History of Human History; University of California, Santa Cruz; State University of Pennsylvania; University of New Mexico; The University of Sao Paulo and other institutions in Argentina, Australia, Belize, Brazil, Chile, the European Union, Peru and the United States.
The researchers received formal licenses for excavating and analyzing ancient human remains and consulted with local government agencies and autochthonous communities.
Clovis bond in the oldest middle and southern Americans
A specific type of DNA that is associated with the Clovis culture was found in Chile, Brazil and Belize 11,000 to 9,000 years ago.
"The key discovery is that a person associated with a Clovis culture from North America, which gave about 12,800 years ago, has shared a distinctive tradition with the oldest Chilean, Brazilian and white people," co-lead author Cosimo Posth of the Mak Planck Institute for Science human history. "This supports the hypothesis that the expansion of people who spread Clovis culture in North America also arrived in Central and South America."
However, in today's South American, Clovis culture is missing, and old samples are less than 9,000 years old.
"This is our second key discovery," said senior author David Reich, a professor of genetics at Harvard Medical School and a researcher at the Hovard Hughes Medical Institute. "We have shown that there has been a population change that began 9,000 years ago."
After replacing the population, there was a striking genetic continuity between ancient individuals who gave up to 9,000 years and modern people from several South American regions. This is different from Western Eurasia and Africa, where there are several places with such long-lasting continuity.
California Channel Island – associated origin in the Andes
Another unknown unknown distribution of human beings has been revealed in the analysis which shows that the ancient Californians from the Channel Islands had a distinctly common origin with groups that had become widespread in the southern Peruvian Andes at least 4,200 years ago.
Researchers say it is unlikely to reflect the spread of the population, especially from the Channel Islands to South America. Instead, they assume that the link between these regions is the result of the expansion of people that happened thousands of years earlier, and that such an origin has become widespread in the Andes after subsequent events in South America.
"It could have been that this origin had arrived in South America thousands of years earlier and we just do not have previous people who show it," said Nathan Nakatsuka, research assistant at Reich Laboratory at Harvard Medical School and one of the main authors of the study. "There is archeological evidence that the population in the central Andes region has significantly gone over 5,000 years ago. The distance between certain subgroups during these events may be the reason why we discover this origin later."
Promise of ancient DNA research in America
Researchers point out that their study gives only a look at discoveries that can come through future work.
To find out about the initial movements of people in Central and South America, they say, it would be necessary to create Ancient DNA from people who date 11,000 years ago.
Even in the period between 11,000 and 3,000 years, on which this study focused, the picture is far from complete.
"There are missing ancient data from Amazon, North America and Caribbean, and therefore we can not determine how individuals in these regions relate to those we analyzed," said Reich. "Filling these gaps should be a priority for future work."
"We are excited about the potential of research in this area," co-author Johannes Krause of the Mak Planck Institute for Human History Science said. "With future research at the regional level with large sample sizes, we could understand the potential of the ancient DNA to discover how the human diversity of this region has become as it is today."
First Nations: The study found that two ancient divisions were "reconstructed" with the settling of South America
Cell, Posth et al .: "Reconstruction of the history of the deep population of Central and South America" DOI: 10.1016 / j.cell.2018.10.027, https: //vvv.cell.com/cell/fulltekt/S0092-8674 (18) 31380 -1