PROVIDENCE, R.I. [Brown University] — How modern-day humans
dispersed on the planet and the pace of civilization-changing
technologies that accompanied their migrations are enduring
mysteries. Scholars believe ancient peoples on Europe and Asia
moved primarily along east-west routes, taking advantage of the
relative sameness in climate, allowing technological advances to
spread quickly. But what about in North and South America, with
its long, north-south orientation and great variability in
climate? How did people move and how quickly did societal
innovations follow? Using advanced genetic analysis techniques,
evolutionary biologists at Brown University and Stanford
University studied nearly 700 locations on human genomes drawn
from more than five dozen populations. They say that technology
spread more slowly in the Americas than in Eurasia and that the
continents’ orientation seems to explain the difference. After
humans arrived in the Americas 20,000 to 40,000 years ago,
genetic data shows, the migrating p