The Bering Land Bridge, which connected Asia and North America during the last ice age, was more of a highway than imagined, say researchers. After analyzing skulls, language, even DNA, some scientists think that the people who populated the Americas came in more than one migration, from several different regions. The theories were presented Saturday at the annual meeting of the American Association for the Advancement of Science. Loring Brace, an anthropologist at the University of Michigan, measured the skulls of ancient and modern humans and found that jaw and teeth sizes vary among populations. His analyses show that the first people to visit the New World came from eastern Asia, in the southern region of the Sea of Ohkotsk.
Brace says five different groups made the long journey.
Geneticist Theodore Schurr agrees. He compared the DNA of American native groups to Asian groups and found several sources. Four major Asian lineages were brought to the Americas, beginning about 25,000 to 30,000 years ago, says Schurr. David Meltzer, an anthropologist at Southern Methodist University, suggests that the reason no one has found convincing evidence to support these theories is that scientists haven't looked in the right places. Meltzer thinks that the first group came along the coastline, not the land bridge.