Earliest Americans Arrived in Waves, DNA Study Finds

North and South America were first populated by three waves of migrants from Siberia rather than just a single migration, say researchers who have studied the whole genomes of Native Americans in South America and Canada....

Archaeologists who study Native American history are glad to have the genetic data but also have reservations, given that several of the geneticists’ conclusions have changed over time. “This is a really important step forward but not the last word,” said David Meltzer of Southern Methodist University, noting that many migrations may not yet have shown up in the genetic samples. Michael H. Crawford, an anthropologist at the University of Kansas, said the paucity of samples from North America and from coastal regions made it hard to claim a complete picture of early migrations has been attained.

“Sometimes the statisticians make wonderful interpretations, but you have to be very guarded,” he said....