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Open access, freely available online Synopses of Research Articles From Few to Many: New World Founded by Surprisingly Small Population DOI: 10.1371/journal.pbio.0030227 About 14,000 years ago—a few hundred thousand years after our putative modern forebears spread out from Africa—descendants of archaic humans crossed the Bering land bridge from Siberia to North America. Several lines of evidence support this model, but that’s where the consensus ends. The details remain hotly debated, focusing mostly on which Asian population migrated, when they did it, and whether they did it more than once. Part of the challenge in reconstructing this history stems from the dynamic nature of human populations—which experience unpredictable changes in size, composition, density, and mating patterns—and the diffi culty in interpreting DOI: 10.1371/journal.pbio.0030227.g001 genetic history. To get a better picture of the range of possible scenarios, scientists Data from nine different regions in the human genome chart the journey of the fi rst are using new statistical approaches that immigration to the New World require computer simulations. Jody Hey IM model has required the assumption His analysis suggests that only about now extends this approach in a novel that all of the populations were constant 70 individuals left their ancestral Asian method for the study of the origins of in size, and therefore it has not been useful population, estimated at about 9,000 New World populations. Along with for assessing how descendant populations individuals, to reach America 7,000 to DNA analysis and computer simulations, arose or changed in size. 14,000 years ago. Archeological evidence Hey adds a new twist to an old model