Many people have recommended I read Johanna Nichols’ Linguistic Diversity in Space and Time over the years. I checked out the book in grad school once but didn’t get around to reading it. But today I see it being referenced in Stephen Oppenheimer’s very strange book about Lemuria-I mean Southeast Asia, Eden in the East.
Both of these books were written in the late 1990s, before the current swell of genome-wide and ancient DNA analysis. Oppenheimer reports Nichols’ comparative analysis of linguistics implies that the ancestors of the Amerindians were not interior Siberians, but coastal people who came up from Southeast Asia.
Today we know this is somewhat wrong. About 30 to 40 percent of the ancestry of modern Native Americans derives from Ancient North Eurasians, who seem to be most commonly found in the great Eurasian heartland, probably to the east of what we think of today as Europe, but west of the Pacific.
But there’s more. Most of the ancestry of Native American peoples seems to be more like that of East Asians. Today this component extends rather far north, into Korea, Japan, and such. But these are consequences of recent demographic movements. Nichols’ Southeast Asian hypothesis may actually not be off-base, in particular in light of other evidence suggesting admixture with an Australo-Melanesian population.
One of the major issues with the field of ancient DNA and the historical inferences people make is that the theories and models are often quite ad hoc, and emerge in response to the data. But these earlier ideas, informed by linguistics and archaeology, are actually a pretty good source of possible ideas. They may not be constrained by genetics, because we didn’t have that information (aside from mtDNA), but are richly informed by other disciplines.