Thursday, April 05, 2018

Not Out Of Africa

For those interested in prehistory and the origins of Anatomically Modern Humans, there is recent evidence that we did not come Out of Africa, or not in the same way as usually imagined.  It is possible that we left before we became AMH, then mixed with Neanderthals and kept a few of their best genes while we were in the Mediterranean, North Africa. Only then did we spread to all parts, including back to sub-Saharan Africa.

There is a second population the East Asians mixed with, the Denisovans, and there is a DNA suggestion that there are at least two other remote hominid populations we interbred with as well, one in Asia and one in Africa. Greg Cochran is discussing at West Hunter all the archaeology and DNA of this in the context of reviewing the new David Reich book, which Cochran likes parts of and disapproves of others.


Christopher B said...

They've been interesting reading though some of the more technical and statistical discussion glazes my eyes a bit.

Still have to notice one thing is still missing.

The Link.

Assistant Village Idiot said...

Cochran notes right off in the comments that it's hard to tell if its an ancestor. Something is clearly an ancestor, but which ones? When you have species close enough for interbreeding and a few thousand years to move around, it's more likely to be an ancestral web rather than a tree. Each of us individually has a tree, but all of us as a whole may not.

Consider a group as well-defined as Scotsmen. Except for recent immigrants, they all have some Celt in them. Lots of them have some English, Dutch, French, and Scandinavian in them, too, though these came in in different centuries, and not everyone has all of them. If we look farther back, lots of those those English, Dutch, French, and Scandinavian also have some Celt in them. So checking the DNA, any Celtic bit probably came from the lines that were in place in Scotland all those centuries. But it might have come in from one of the French lines that married in 400 or 800 years ago. Whenever you have a population mixing, it's not likely all on one Saturday night in 1187 BC, all in the same valley. (Though with Mongol invaders something like that does happen.)

Christopher B said...

That was some of the more interesting stuff to me - how fast different groups will show noticeable DNA differences but how long interbreeding remains possible.