An ancient DNA discovery rewrites the history of South America and Central America – Quartz

The analysis of the remains of 49 people revealed that there were at least three large waves of immigration from North America to South America, instead of the same. only one, as scientists once believed.

The researchers so far knew only the first migrants, who arrived in South America at least 11,000 years ago. However, the analysis of DNA published in Cell on November 8th suggests that a second group of settlers replaced the former about 9,000 years ago. And a third group arrived in South America about 4,800 years after that.

An international team of geneticists, including those from the Harvard Medical School in the United States and the Max Planck Institute for the Science of Human History in Germany, analyzed the genomes of the skeletal remains of 49 found in Belize, Brazil, in the central Andes (which includes parts of Ecuador, Bolivia, and Peru) and the southern cone of South America (which includes Argentina, Chile, Uruguay and parts of Brazil). Of these 49 people, 41 were over 1,000 years old.

Not only did these works reveal three distinct gene flows to South America, but they also revealed that around 9,000 years ago, the genes of the first wave of migrants have almost completely disappeared. This suggests that the second wave of migrants replaced the first, although the way this happened is unclear.

A separate study of 15 different human genomes found in the Americas, ranging from modern Alaska to Patagonia (six over 10,000 years old) published the same day in Science, shows the movement of people across the continent. Research has also shown that some of the remains found in Brazil have an indigenous Australasian genetic biomarker. Scientists have speculated that the genetic link between former Australasians and former Brazilians is due to migrants traveling by land. But since there is no genetic trace of this journey among the remains of a skeleton between the two continents, this remains a mystery.

That said, one thing is clear: these ancient peoples were going fast. "People were spreading like fire in the landscape and adapting very quickly to the different environments they encountered," Eske Willerslev, a geneticist at Denmark's Museum of Natural History in Copenhagen and co-author of Science. study told Science News.

The two newspapers are among the first to show the complex variation of movements among the populations that made up the first migrants in South America. "I think this series of documents will be remembered as a first glimpse into the real complexity of these multiple settlement events," said Nature an archaeologist from Alaska-Fairbanks University, Ben Potter. "It's awesome."