I can't believe there is only one (other) top-level comment in this thread, and it's basically anti-science. It doesn't matter what you "subscribe" to, what matters are theories backed by scientifically collected data.
>This new picture raises a key question: did the first migrants to the Americas really race over Beringia just as the great ice sheets were melting?<p>I'm not sure that I subscribe to land bridges as gateways for early humans to move between continents, especially in the north. The Inuit/Eskimo peoples are and were perfectly capable of moving and living on water, frozen water but water nevertheless. Humans need not have waited to walk across dry land bridges. They were perfectly capable of migrating along ice sheets, or even setting out into open oceans. It would not have been much fun, but the journey would have been made either deliberately or by accident.