Analysis of the remains of 49 people has been present at least three major immigration waves from North to South America, rather than just one, as scientists previously believed.
Researchers to date only knew of the first migrants who arrived in South America at least 11,000 years ago. But DNA analysis published in Cell on November 8 suggested that a second group of settlers replace the first 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 US and the Max Planck Institute for the History of Human History in Germany, analyzed the genome of the 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 (which includes Argentina, Chile, Uruguay, and parts of Brazil). Of those 49, 41 were more than 1,000 years old.
Not only did this work reveal the three distinct flows of genes to South America, so researchers found that around 9,000 years ago. This suggests that the second wave of migrants replaced the first, though it's not clear how this happened.
A separate study of 15 different human genomes found in the Americas, ranging from modern-day Alaska to Patagonia (six of which was older than 10,000 years) published on the same day in Science, shows the movement of populations across the continent. The research thus had some indigenous Australasian genetic biomarker. The scientists hypothesize that the genetic connection between ancient Australasians and ancient Brazilians is due to migrants traveling by land. But, it's still a mystery.
That said, one thing is clear: these ancient people were moving fast. They were encountering, "Eske Willerslev, geneticist at the Natural History Museum of Copenhagen Denmark and co-author of the Science study told Science News.
The two papers are the first to show the intricate variation of movement among the populations that made up the first migrants to South America. Ben Potter, an archeologist at the University of Alaska-Fairbanks, said: "I think this series of papers will be remembered as the first glimpse of the real complexity of these multiple peopling events." "It's awesome."