This is going to be a lot to chew on, and I suspect the genetic argument will win out in the final analysis. Maybe Cogs has some thoughts here.
Beags, thanks for the kudos but it has been decades since I studied genetics. And that was molecular genetics with an emphasis on pathology under Stanley Falkow at the Univ. of Washington in Seattle (reference:
http://en.wikipedia.org/wiki/Stanley_Falkow ). In reviewing Bednarik's article:
1. Bednarik believes that
cultural selective breeding for gracile traits progressively reduced robust genes (first in the females) in all world populations over the last 40,000 years in addition to genetic drift and introgression. He states that this type of selective breeding is continuing today.
2. Bednarik maintains that there is no evidence of mass migration from Africa prior to 28,000 years ago and that the Aurignacians display definite Neanderthaloid characteristics while their technologies are attributed to moderns who are not found in the archaeological digs.
3. Bednarik believes the genetic clock being used to differentiate HSS from Neanderthals is flawed and states further the difference in genetics between Neanderthals and moderns are minimal. He refers to Neanderthals as
H. sapiens neanderthalis.
In dealing with his first point, I do not believe Bednarik can convince anyone that worldwide cultural selective breeding for gracile characteristics is realistic without outside influence. As evidenced in North America, Clovis points rapidly spread through an existing population since the technology put more food on the table (reference:
http://news.nationalgeographic.com/news ... ans_2.html ). However, in this case gracile genetics are required (a donor). Most cultures will readily accept improvements and, quite possibly, we are experiencing the first evidence of the traveling salesman on the move, sowing gracile genetics through a robust population. If it becomes slightly easier for a female to give birth to a gracile hybrid due to reduced head volume -- Voila! A takeover of the local genome has occurred over a few generations. However, our salesman needed to bed this babe:
I find Bednarik's second point most interesting and in conformity with recent research by Trinkaus, Wolpoff and others (see:
http://sci.tech-archive.net/Archive/sci ... 00006.html ). There is no evidence that the Aurignacians were anything but robust specimins, and possibly Neanderthals that were becoming hybridized due to introgression. However, no gracile specimens are found in Europe prior to 28,000 years ago while the Aurignacian culture was evident from at least 40,000 years ago. The morphology of finds points to robust hybrids. Do they leave any traces in today's genetics? Probably not, with the possible exception of the brain D allele (see:
http://www.pnas.org/cgi/content/abstract/0606966103v1 ) and FOXP2 (see:
http://johnhawks.net/weblog/reviews/nea ... _2007.html ). Wolpoff argues that Neanderthal characteristics are still evident in today's population.
Bednarik's argument with a "selective" genetic clock being used to track haplogroups is probably valid. However, it doesn't mean OOA is dead. It simply means that OOA started to fan out in significant numbers more recently, and that many of the haplogroup families were established in Africa prior to leaving home. The human genetic family tree still demonstrates that our haplogroups originate in an unbroken string back to Africa even though the timing might be off.
Estimating where and when haplogroups showed up using a genetic clock based on an inexact science is a hazardous profession since the results can be off by orders of magnitude. There is a
dirty little secret in the lab: anomolous results are "thrown out" and often there is pressure to smooth the data points to match the expected outcome. Talk to any scientist after a few beers. Proutsch took it to an extreme by just guessing; however, others try to do their best with less than adequate source materials on hand, equipment, etc.
I expect to see a scenario where OOA populations really didn't impact Eurasia until after the LGM about 24,000 years ago. Prior to then, they would simply have incorporated into a homegrown population, hybridizing in some cases. Later on, when the effects of the LGM decreased local populations to the breaking point, in comes OOA in a big way to take over real estate, picking up genes through hybridization along the way. It makes more sense to me from a timeline standpoint. Given that the human genome was widely variable prior to the bottleneck I prefer the following nomenclature for those populations surviving the Toba event:
H. sapien sapien
H. sapien neanderthalis
H. sapien erectus
Further, there is a wildcard that was thrown into the mix as outlined by John and others:
boats and hematite. Gracile characteristics could have spread from worldwide maritime activities as early as 40-60,000 years ago. This is not a total replacement scenario such as OOA, but a gradual conversion of populations from robust to gracile due to consistent and recurring contact with gracile mariners who traveled to explore the seas out of curiosity. It's called wanderlust.
