The first people to settle the Americas had a distinctive genetic style, and additional waves of migrants added regional flair, a new analysis of mitochondrial DNA from Native Americans from Canada and the United States suggests.
About 15,000 to 18,000 years ago, the first migrant wave spilled from Asia down the Pacific coast and then pushed inland, eventually peopling the land from “the tip of South America all the way to Hudson Bay,” says Andrew Kitchen, a genetic anthropologist at the University of Iowa who was not involved in the new research. That first migrant wave contained the ancestors of all South and Central American tribes, and North Americans, too. But something different was going on in North America, an international team of researchers has discovered.
The scientists examined the DNA of mitochondria, tiny power plants within cells that get passed down from mother to child. Scientists use mitochondrial DNA from living populations to decipher ancient movements of their ancestors. Most studies have examined only a small part of the mitochondria’s circular piece of DNA. But Antonio Torroni, a geneticist at the University of Pavia in Italy, and his coauthors compiled complete mitochondrial genomes from 41 native North Americans and combined that data with information from previous studies.
The result is the clearest picture yet of the complicated movements of people into the Americas, says Theodore Schurr, a molecular anthropologist at the University of Pennsylvania.