from Beringia to the Americas did so via two routes — one along the Pacific Coast and another by an inland path east of the Rocky Mountains … .They trace two rare mitochondrial DNA haplotypes (D4h3a and X2a), early migrations that would have been both about the same time. It looks like the former group spread down the west path to South America, while the latter are found in the areas on the map here.
the scenario of a structured and temporally changing Beringian source population makes it most unlikely that only a single language family was carried along with the first Pleistocene groups of migrants. Some of these different languages may have been in close contact for several hundred years in Beringia and on the move into the Americas, rendering a distinction between contact features and inherited traits virtually impossible in retrospect after a few thousand years.It's nice to see a papper like this noting the likelihood of pre-migration contact in Beringia. In fact, it seems like part of a general argument against simplistic scenarios on this topic.
I'm pretty swamped these days, but we have a couple of minions out in San Francisco for the Linguistic Society of America and American Dialect Society, so we should have some reports from out there.
*I count a total of 16 co-authors.