It is a fortuitous coincidence that there actually is a sample of humans from Northwest Africa from around the same time: Jebel Irhoud, about 160 thousand years ago from Morocco:
Jebel Irhoud is a cave site located about 100 km west of Marrakech, Morocco. The site is known for the numerous hominid fossils discovered there. Currently, the site has yielded seven specimens. The best known of these are portions of two adult skulls, Irhoud 1 and 2, a child’s mandible (Irhoud 3), and a child’s humerus (Irhoud 4). Fossils 1-3 were discovered while the cave was being quarried for barytes and thus their exact context and age has been subject to debate. Originally the Irhoud hominids were considered North African Neandertals. It is now clear that they are best grouped with other early anatomically modern humans such as Qafzeh (Israel) and Skhul (Israel).
A 2007 article by Smith et al. is extremely important for this population:
Earliest evidence of modern human life history in North African early Homo sapiensIn the recent paper on the Ceprano calvarium, Irhoud 1 clearly belonged in the modern human cluster, and so it was in my re-analysis of that data, as were skulls from the Sudan and Tanzania in Africa, and the Qafzeh/Skhul early skulls from the Levant.Tanya M. Smith et al.
Recent developmental studies demonstrate that early fossil hominins possessed shorter growth periods than living humans, implying disparate life histories. Analyses of incremental features in teeth provide an accurate means of assessing the age at death of developing dentitions, facilitating direct comparisons with fossil and modern humans. It is currently unknown when and where the prolonged modern human developmental condition originated. Here, an application of x-ray synchrotron microtomography reveals that an early Homo sapiens juvenile from Morocco dated at 160,000 years before present displays an equivalent degree of tooth development to modern European children at the same age. Crown formation times in the juvenile's macrodont dentition are higher than modern human mean values, whereas root development is accelerated relative to modern humans but is less than living apes and some fossil hominins. The juvenile from Jebel Irhoud is currently the oldest-known member of Homo with a developmental pattern (degree of eruption, developmental stage, and crown formation time) that is more similar to modern H. sapiens than to earlier members of Homo. This study also underscores the continuing importance of North Africa for understanding the origins of human anatomical and behavioral modernity. Corresponding biological and cultural changes may have appeared relatively late in the course of human evolution.
It thus seems to me, that the earliest modern human skulls are found in North/East Africa and West Asia, while the root of the Y-chromosome phylogeny is provisionally in Northwest Africa and seems to be in agreement with the autosomal evidence for a bottleneck in the human population at around 150,000 years ago.
Here is the interesting part: Irhoud had been once seen as a Neandertal. Indeed, it displayed some Neandertal-like leanings in a previous analysis. The consensus now (supported by the results of Mounier et al.) seems to be that it was modern human, but the Neandertal connection does not stop there:
The lithic industries of Jebel Irhoud were Mousterian, the same as Neandertals. Mousterian industries link European Neandertals, with modern humans in North Africa and the Near East. The Mousterian industries represented a genuine progress over the Acheulean tools that archaic humans had been using for hundreds of thousands of years before, and they, in turn, were replaced by the Aurignacian at exactly the time that Cruciani et al. date the main Y-chromosome CT clade that encompasses all Eurasians and most Africans.
The evidence seems to be in astonishing agreement with my hypothesis about the so-called "Neandertal admixture" in modern humans:
- Early modern humans originated in North Africa, or at least somewhere between North and East Africa. Their traces may very well be hidden under the sands of the once (or thrice) green Sahara
- They formed a clade with Neandertals, and used the same Mousterian tools, while humans elsewhere continued to use the older Acheulean ones. Both of them could very well have descended from Homo heidelbergensis, although the transition is not yet clear.
- They expanded briefly into West Asia after Marine Isotope Stage 5, 120,000 years or so ago, and appeared in the Levant (Skhul/Qafzeh). As the Sahara dried up, they must've spread both to West Asia, and deeper into Africa, and, not surprisingly, the next major branching of the Y-chromosome phylogeny dates to about that time; this accounts for the deep (but not deepest) Y-chromosome lineages in modern day San.
- Eventually (around 40,000 years ago, after the end of wet Marine Isotope Stage 3), they developed the even more advanced Aurignacian technology, and went on to conquer most of the world, driving the Neandertals to extinction. As the Sahara dried up, they expanded into Sub-Saharan Africa once again, and this time they inundated it with their genes.
The model in brief
195 ka: Anatomically modern humans appear in East Africa (Omo skulls)
160 ka: Mousterian-using modern humans in North Afrca (Jebel Irhoud)
142 ka: Y-chromosome Adam
MIS 5 120-110 ka: Demographic expansion of modern humans in Sahara during this wet phase, followed by collapse as Sahara becomes dry; escape to West Asia and Sub-Saharan Africa; possible admixture with Neandertals and Acheulean-using Palaeoafricans respectively.
MIS 3 50-45 ka: Second demographic expansion of modern humans in Sahara, followed by collapse as Sahara becomes dry; development of Aurignacian
after 45 ka: Colonization of Eurasia and Sub-Saharan Africa by modern humans sensu stricto: anatomically and behaviorally modern people with advanced tools. Most human Y-chromosomes (belonging to C, DE, and F) coalesce to this period.
40 ka: Neandertals extinct after contact with modern humans (absorbed/killed?); some survive in periphery
Today: Most living humans descended from post 45-ka expansion people. Sub-Saharan Africans shift away from Eurasians due to a little archaic African admixture. Papuans shifted away from Eurasians due to "Denisovan" admixture. Contribution of other archaic hominins to regional Homo sapiens populations TBD.