“There were giants in the earth in those days; and also after that, when the sons of God came in unto the daughters of men, and they bare [children] to them, the same [became] mighty men which [were] of old, men of renown.”
The Pith: Pygmies and Khoisan have admixture from a distinct population at the level of ~2%. This population diverged from the other ~98% of their ancestry ~700,000 years before the present, and the hybridization occurred ~30-40,000 years before the present. Most other African groups have only traces of this element, with some West Africans lacking it.
I have read the paper in PNAS which I referred to below. There isn’t that much I can add at this point. A lot of the guts were pushed into the supplements, which aren’t on the web yet. I was correct that the Mbuti Pygmies of the eastern Congo likely have a special place in this possible admixture event. In particular, they seem to possess the diverged variants found in the western Pygmies, the Biaka, and the Khoisan populations of southern Africa. As assumed the pattern of admixture seems to be such that the two Pygmy groups and the Khoisan exhibit elevated signatures of archaic contributions, while other African groups manifest admixture in direct proportion to their known admixture to the aforementioned populations. For example, the Bantu group with the highest proportion of admixture are the Xhosa, who also have the most Khoisan ancestry of non-Khoisan populations. The West African Mandenka seem to have trivial admixture from this archaic group. What does this mean?