Homo sapiens: 'Out of Africa' three distinct times, new analysis shows
Posted on 02/10/2006 2:54:05 AM PST by PatrickHenry
A new, more robust analysis of recently derived human gene trees by Alan R. Templeton, Ph.D, of Washington University in St Louis, shows three distinct major waves of human migration out of Africa instead of just two, and statistically refutes — strongly — the 'Out of Africa' replacement theory.
That theory holds that populations of Homo sapiens left Africa 100,000 years ago and wiped out existing populations of humans. Templeton has shown that the African populations interbred with the Eurasian populations — thus, making love, not war.
"The 'Out of Africa' replacement theory has always been a big controversy," Templeton said. "I set up a null hypothesis and the program rejected that hypothesis using the new data with a probability level of 10 to the minus 17th. In science, you don't get any more conclusive than that. It says that the hypothesis of no interbreeding is so grossly incompatible with the data, that you can reject it."
Templeton's analysis is considered to be the only definitive statistical test to refute the theory, dominant in human evolution science for more than two decades.
"Not only does the new analysis reject the theory, it demolishes it," Templeton said.
Templeton published his results in the Yearbook of Physical Anthropology, 2005.
A trellis, not a tree
He used a computer program called GEODIS, which he created in 1995 and later modified with the help of David Posada, Ph.D., and Keith Crandall, Ph.D. at Brigham Young University, to determine genetic relationships among and within populations based on an examination of specific haplotypes, clusters of genes that are inherited as a unit.
In 2002, Templeton analyzed ten different haplotype trees and performed phylogeographic analyses that reconstructed the history of the species through space and time.
Three years later, he had 25 regions to analyze and the data provided molecular evidence of a third migration, this one the oldest, back to 1.9 million years ago.
"This time frame corresponds extremely well with the fossil record, which shows Homo erectus expanding out of Africa then," Templeton said.
Another novel find is that populations of Homo erectus in Eurasia had recurrent genetic interchange with African populations 1.5 million years ago, much earlier than previously thought, and that these populations persisted instead of going extinct, which some human evolution researchers thought had occurred.
The new data confirm an expansion out of Africa to 700,000 years ago that was detected in the 2002 analysis.
"Both (the 1.9 million and 700,000 year) expansions coincide with recent paleoclimatic data that indicate periods of very high rainfall in eastern Africa, making what is now the Sahara Desert a savannah," Templeton said. "That makes the timing very amenable for movements of large populations through the area."
Templeton said that the fossil record indicates a significant change in brain size for modern humans at 700,000 years ago as well as the adaptation and expansion of a new stone tool culture first found in Africa and later at 700,000 years expanded throughout Eurasia.
"By the time you're done with this phase you can be 99 percent confident that there was recurrent genetic interchange between African and Eurasian populations," he said. "So the idea of pure, distinct races in humans does not exist. We humans don't have a tree relationship, rather a trellis. We're intertwined."
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Ah Dam Bubba now what ya gonna do with all them hoods?
"Templeton said that the fossil record indicates a significant change in brain size for modern humans at 700,000 years ago..."
"Heyyyyy...wait a minute...we're still in Africa! OOweena! Get the kids...we're leavin!"
A very neat illustration of the self-correcting mechanism in scientific methodology, and Popper's principle of "falsifiability". I have marvelled to witness, on another thread here, that a number of folks don't seem to understand the scientific meaning of 'theory,' and insist on using the term in its vernacular sense. Theory of Evolution is not controversial outside the US (at least, not in the developed western world), it is simply subject to increasing refinement as more data points are accumulated, as is any scientific theory.
Is he saying that we do have a genetic intermix with Neanderthal or not? they supposedly went belly up around 35,000 years ago, but he wasn't talking about that time frame. I suppose if Neanderthal migrated back to africa over various periods of time that they are in our DNA and not just a dead end, but he is not that specific.
Just wanted to make sure you'f seen this...
if we have any neanderthal DNA....it votes dem
Didn't read the article yet but it's easily provable we have Neanderthal DNA. All ya hafta do is see a picture of my wife and her brothers.
Course she claims the same is true with me...sigh.
prisoner6
no its the 'out of Africa' DNA that votes the Ray Nagin, Barak Obama, and Bill Clinton (our first black prez).
While my 'Neaderthal' blood would vote for a Condi Rice (prez? why not) or a JC Watts for whatever. and Bless Judge Thomas and Judge Janice Rogers Brown.
Okay, maybe the coffee hasn't kicked in yet, but what's the difference?
Well said.
Please add me to your ping list.
p.s. I'm a Catholic so I don't have a dog in the evolution fight, it just bugs me when I read something and I still don't get it.
I'm Cahtolic as well, but I think it is saying something taht we've ALL ben taught. The only 'race' is the human race.
Unfortunately, the first over-educated intellectuals developed right after that.
The theory of evolution is not controversial here. For lack of education or whatever, some people refuse to accept it. But their lack of any provable alternative and ability to formulate one does not make evolution controversial. Among the rest of the thinking and educated America, evolution is as accepted as the theory of gravity. IMHO, of course.
Maybe this explains why I have a thing for black chicks.
I believe it's a compelling argument. The out of Africa theory never explained the differences that are the various races of mankind, but if there were several migrations over the millenium, then this would account for these differences very nicely.
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