Analysis of the remains of 49 people revealed that from North to South America there were at least three major immigration waves, instead of just one, as scientists previously believed.
Researchers so far only knew about the first migrants who arrived in South America for at least 11,000 years. But DNA analysis published in Cell on November 8 suggests that the second group of settlers replaced the first about 9,000 years. And the third group arrived in South America about 4,800 years after that.
The international team of geneticists, including those from Harvard Medical School in the United States and the Max Planck Institute for Human History in Germany, analyzed the genome of skeletal remains of 49 people found in Belize, Brazil, the Central Andes (which includes parts of Ecuador, Bolivia and Peru), and the southern cone of South America (including Argentina, Chile, Uruguay and parts of Brazil). Of these, 49, 41 years had more than 1,000 years.
Not only did this work reveal three different gene flows in South America, and researchers also found that genes from the first wave of migrants nearly disappeared almost 9,000 years ago. This suggests that the second wave of migrants has replaced the first, although it is unclear how this has happened.
A separate study of 15 different human genomes in America, ranging from modern Alaska to Patagonia (six of which was older than 10,000 years) published the same day in Science, shows a population movement across the continent. The research also showed that some of the remains found in Brazil had indigenous Australasian genetic biomarkers. Scientists assume that the genetic link between old Australians and ancient Brazilians is the result of migrants traveling by land. But since there are no genetic traces of this journey from any skeletal remains between the two continents, it is still a puzzle.
That said, one thing is clear: these ancient people are moving fast. "People spread like fire across landscapes and quickly adapted to the different environments they met," said Eske Willerslev, a geneticist at the Danish Museum of Natural History in Copenhagen and co-author of science the Science News study was studied.
Two newspapers are the first to show the intricate variation of movement among the populations that made the first migrants in South America. "I think this series of works will be remembered as the first insight into the real complexity of these multiple events," he told Nature of Nature Ben-Potter, an archeologist at Alaska-Fairbanks University who was not involved in the studio. "It is nice."