What a great day for paleo-anthropology!
Why?
A couple of months ago a paper published the results of dating of remains that showed that homo sapiens sapiens of modern anatomy were living in North Africa by 300,000 years ago...this pushed back the homo sapien emergence time line some what as these finds were older than the well known finds in East Africa thousands of miles away.
At the time, lazy and irresponsible conjecture on the matter supposed that the cradle of homo sapiens may not have been the rift valley but was instead north africa...this is nonsense for several reasons:
1) North Africa at the time did not present the complex combination of environmental factors that enabled the natural thriving of humans ...making it likely it was a place they moved to from some where else rather than evolved in situ.
2) Modern analysis of genetic lineages in Africa all center to lineages that are either in the east or southern regions of the continent...almost the furthest places you can be from North Africa while still being in Africa...this is important as geographic distance correlates with lineage proximity with more distally dispersed lineages more likely to be unrelated...taken together with the dating estimates the east and south african finds which are both more numerous than the north african ones ...point to that area as the hot map for human origins.
3) The rift valley presents a very well known and obvious cooking pot for human evolution due to the environmental shift that attended the region over the last few million years...where there is environmental selection extant species tend to diversify...this is true of birds and and reptiles and it is also true of humans.
4) Given 3) above ...we see primates in the area were also subject to radiative adaptation... Gorillas diversified, Chimpanzees diversified (Bonobo's are classified as a distinct sup species) and we know from ancient hominin lines ...that homo diversified...again all this is centered over the central to east African rift region...making it a hot bed for any emergence of new species relative to other environmentally stable regions of the continent during the time.
All that said, this new result which centers on genetic information taken from 15,000 year old samples, the oldest yet genetically sequenced from Africa...shows clearly what intelligent hypothesis on the human lineage migrations from their east African centers should show....
a) The individuals had more Sub Saharan African than modern day North Africans.
b) The individuals had near eastern admixture predominating.
c) The individuals showed no indication of admixture from South Europeans.
Often in the wild discussions that describe North Africa as non African the argument is made that they had been mixing with Southern Europeans for thousands of years...though more recent data shows this is quite certainly the case for at least 3,000 years ...not much had been known regarding further points in time ...prior to Agriculture being invented in the near east about 10,000 years ago.
Now with no signal in these people the likelihood is very strong that European admixture is relatively new.
It's also true that the near eastern admixture is very old indeed with trade and migration through the levant being so heightened as to have already created a distinct "near eastern" genetic finger print by 15,000 years ago...consider at this time other human lineages, the ancestors of the Siberian Yakut were just getting to the Baring land bridge to cross and start populating a New World empty of any hominids.
This may explain why the ancient Egyptians looked like they did...they inhabited a particularly unique range of admixtures between the ancestral sub Saharan stock from which they derived which over the 150,000 to 200,000 years of migration across North Africa and by 110,000 years ago through the levant...evolved into the near eastern genetic profile...an amalgam of adaptations to live in North African and Levant and South Asian environments over a period of 100,000 years.
The climate variations induced by the heightening of the glacial maximum variably opening and closing the North to the South ...and explaining the loss of continued genetic input in favor for more with the levantine near eastern lineages that emerged and then much later around 3 to 5,000 years ago the South European.
I hypothesize that should more such finds from this era be made we will see that the further back the dated material the more Sub /East African admixture will be found...in fact it could very well be that being in Morocco this particular find was an outlier on a broader genetic similarity across the North ...particularly to regions closer to the Nile which likely formed the main migration conduit through the Sahara as it went from arrid to arable with the glacial cycles over the last several hundred thousand years.
The paper:
https://drive.google.com/file/d/1pX7qNGW8FYb2sJ7MT-bFImMtF1b_Z4fR/view?usp=sharing
Comments