for National Geographic News
A consensus is emerging in the highly contentious debate over the colonization of the Americas, according to a study that says the bulk of the region wasn't settled until as late as 15,000 years ago.
Researchers analyzed both archaeological and genetic evidence from several dozen sites throughout the Americas and eastern Asia for the paper.
"In the past archaeologists haven't paid too much attention to molecular genetic evidence," said lead author Ted Goebel, an archaeologist at Texas A&M University in College Station.
"We have brought together two different fields of science, and it looks like they are coming up with the same set of answers."
The article, which is published in tomorrow's issue of the journal Science, shows that the first Americans came from a single Siberian population and ventured across the Bering land bridge connecting Asia and North America about 22,000 years ago.
The group got stuck in Alaska because of glacial ice, however, so humans probably didn't migrate down into the rest of the Americas until after 16,500 years ago, when an ice-free corridor in Canada opened up.
(Related: "New World Settlers Took 20,000-Year Pit Stop" [February 14, 2008].)
Clovis Not First
Scientists have long agreed that the first Americans came from northeast Asia, according to Goebel.
But the new article—which analyzed genetic and archaeological evidence from 43 sites, including a dozen sites in Asia—better pins down the makeup of the first Americans.
Genetic evidence, for instance, points to a founding population of less than 5,000 individuals.
Some geneticists had also previously suggested that the migration across the land bridge could have occurred as early as 30,000 years ago.
SOURCES AND RELATED WEB SITES