Monday, June 09, 2008

Tracing Humanity's Path

I just stumbled across this article that came out a couple of weeks ago, describing a statistical modeling study using genomic evidence that attempts to map how our species spread from Africa to populate the rest of the world. I'm really surprised this hasn't gotten more play in the press.

What I found most interesting (from my parochial point of view) was what it had to say about the peopling of the New World:

"The team also found that North and South America were colonized independently by at least two different waves of migration from different parts of Asia, although both waves appear to have arrived via the Bering Strait. This conclusion contradicts the conventional view, which postulates just one migratory wave out of Asia."

These results, if true, add more fuel to the ferment that Paleoindian studies is in and could conceivably support the coastal migration hypothesis we have discussed often here. I'll just restate the opinion I expressed in a post last fall:

"I believe it is starting to appear that the paradigm we have been using for he last 50 years or so, of a single overland migration across Beringia about 14,000 BP, is impossibly simplistic. I think future research will likely show that (as Valerius Geist believes) there were many attempts to colonize the Americas from Asia over a long period of time, both overland and down the coast in boats. We aren't recognizing or haven't found the inland sites and sites along the coast have been drowned by the Holocene rise in sea level.

There is all sorts of evidence that currently doesn't fit together very well. Mitochondrial DNA evidence from Native Americans seems to indicate a single migration of a small number of individuals. But the morphology of the earliest Paleoindian skeletons we have is distinctly different from modern Native Americans. A recent review of all the radiocarbon dates from all the Paleoindian sites in Alaska shows that the oldest sites there are younger than the oldest good dates from further south in North America. That doesn't seem to fit with a Beringian migration. Time and more research will tell. I think we'll see that Clovis was the latest and most successful colonizing attempt."


Chas S. Clifton said...

And don't you just love the fact that testing coprolites -- like these that are pre-Clovis -- appears to get around the tribes' NAGPA objections?

Reid Farmer said...

Exactly right, Chas! I hadn't thought of it that way.

Shame we can't find more coprolites.

Of course grave goods are covered under NAGPRA. I'm sure they could find a lawyer who could argue coprolites should too.

Mike Spies said...

FED: Say, is that a turd in your pocket?

ANTHROPOLOGIST: Ah, yes, but a fossilized turd.