The Neanderthal story is quickly
fleshing itself out. It also answers the
question of the likely source of the genetic variation across Eurasia
and includes traits such as white skin and red hair. Half a million years is enough time to sort
out such specialized traits as we now take for granted. I am not so sure if we cut the time frame to
fifty thousand years.
I suggest that it is safe to
presume that Neanderthal intermarriage precipitated the modern Eurasian
groupings and the general down sizing was strictly a result of the shift to
agriculture. The advent of new peoples pursuing
husbandry brought rapidly rising populations that simply absorbed the Neanderthals.
There will be plenty more to
understand before this is all done but I think that we can be aggressive in our
speculations. A lot of interesting
questions can now be asked and I suspect that we will continue to be surprised.
This is early days..
Genetic research confirms that non-Africans are part Neanderthal
by Staff Writers
Neanderthals, whose ancestors left Africa about 400,000 to 800,000
years ago, evolved in what is now mainly France, Spain, Germany and Russia, and
are thought to have lived until about 30,000 years ago
Some of the human X chromosome originates from Neanderthals and is
found exclusively in people outside Africa, according to an international
team of researchers led by Damian Labuda of the Department of Pediatrics at the
University of Montreal and the CHU Sainte-Justine Research Center. The research
was published in the July issue of Molecular Biology and Evolution.
"This confirms recent findings suggesting that the two populations
interbred," says Dr. Labuda. His team places the timing of such intimate
contacts and/or family ties early on, probably at the crossroads of the Middle East .
Neanderthals, whose ancestors left Africa about 400,000 to 800,000
years ago, evolved in what is now mainly France, Spain, Germany and Russia, and
are thought to have lived until about 30,000 years ago.
Meanwhile, early modern humans left Africa
about 80,000 to 50,000 years ago. The question on everyone's mind has always
been whether the physically stronger Neanderthals, who possessed the gene
for language and may have played the flute, were a separate species or could
have interbred with modern humans. The answer is yes, the two lived in close
association.
"In addition, because our methods were totally independent of
Neanderthal material, we can also conclude that previous results were not
influenced by contaminating artifacts," adds Dr. Labuda.
Dr. Labuda and his team almost a decade ago had identified a piece of
DNA (called a haplotype) in the human X chromosome that seemed different and
whose origins they questioned. When the Neanderthalgenome was
sequenced in 2010, they quickly compared 6000 chromosomes from all parts of
the world to the Neanderthal haplotype. The Neanderthal sequence was present in
peoples across all continents, except for sub-Saharan Africa, and including Australia .
"There is little doubt that this haplotype is present because of
mating with our ancestors and Neanderthals. This is a very nice result, and
further analysis may help determine more details," says Dr. Nick
Patterson, of theBroad Institute of MIT and Harvard University,
a major researcher in human ancestry who was not involved in this study.
"Dr. Labuda and his colleagues were the first to identify a
genetic variation in non-Africans that was likely to have come from an archaic
population. This was done entirely without the Neanderthal genome sequence,
but in light of the Neanderthal sequence, it is now clear that they were
absolutely right!" adds Dr. David Reich, a Harvard Medical School
geneticist, one of the principal researchers in the Neanderthal genome project.
So, speculates Dr. Labuda, did these exchanges contribute to our
success across the world? "Variability is very important for long-term
survival of a species," says Dr. Labuda. "Every addition to the
genome can be enriching." An interesting match, indeed.
very interesting, actually what I've suspected, maybe I heard this before somewhere?
ReplyDelete