A few days ago I posted on some problems with Stephen Oppenheimer’s The Real Eve. Over the next week I’ll be offering a few summations of major points in the “meat” of the book.
One of the most important points in in Oppenheimer’s narrative is that there was only path Out-of-Africa. This is in sharp contrast to the story told in Spencer Wells’ Journey of Man, which argues for two paths Out-of-Africa, one north toward Central Asia, and another south along the India ocean. Oppenheimer argues that:
1) The the initial foray of modern humans into the Levant left no issue. Larger migrations were not possible because of the extremely dry conditions that prevailed throughout much of the Ice Age.
2) All humans owe their ancestry to a group of “beach combers” that crossed into southern Yemen from the Horn of Africa and pushed their way along the Indian Ocean coast into the Indian Continent where they found more amiable conditions.
3) It is from India that the various Eurasian lines pushed east, north and west.
If you want the other narrative, I suggest Journey of Man or this paper that plays up the central role of Central, rather than South, Asia. It is important to note that the two narratives work with the same data set, but tend to play up different aspects. In some places, it seems to me that the data is thin on the ground (Oppenheimer disagrees with Chris Stringer on whether there was a “remnant” of modern humans in Egypt that eventually settled Europe and the Levant-he makes a good case, but I also know that Chris Stringer is a really big name, and it would be foolish to casually dismiss him).
One of the major points that Oppenheimer harps on is that India is the major node in Eurasia. He argues that the origin of most Eurasian haplogroups can be found in the subcontinent. One thing he does leave out is that some researchers disagree on the details with Toomas Kivisild, one of the scientists Oppenheimer cites copiously, on India and its haplogroups.
To get to the crux of the issue, here are two papers that offer alternative conclusions about the same haplogroups:
The Genetic Heritage of the Earliest Settlers Persists Both in Indian Tribal and Caste Populations – which supports Oppenheimer’s position.
and
Independent Origins of Indian Caste and Tribal Paternal Lineages – which flies in the face of some of Oppenheimer’s assumptions.
Of course, it doesn’t help that:
1) NRY & mtDNA lines might not be totally accurate about what really happened.
2) Back-migration can really confuse the issue. Oppenheimer states baldly that once the original groups went their separate ways from South Asia, there wasn’t mixing. It makes life easier when it comes to interpreting the data, but I’m not sure it’s realistic, and even Oppenheimer talks about back-migration of YAP to Africa, and the mixing of lineages in China and the Americas.
I am not convinced by Oppenheimer that there was only one migration out of Africa, but as a lay person, he has made a good case that the move north out of Africa would have been difficult via the Sudan and Egypt into the Levant.
You can see a map here that makes things clearler, note how similar it is to Spencer Wells’ map.
Posted by razib at 10:40 PM