Closing the Out of Africa migratory loop

Related to Muhammad?Credit: Ian Beatty Last year a paper came out in AJHG which reported that Ethiopian populations seem to be a compound of West Eurasians and Sub-Saharan Africans. This is result itself is not too surprising for a host of reasons. First, Ethiopians and other populations of the Horn of Africa are physically equidistant between West Eurasians and Sub-Saharan Africans. 20th century physical anthropologists sometimes placed them in the "Caucasoid" racial classification for this reason. Second, the languages of the Horn of Africa have Afro-Asiatic affinities. The Cushitic languages (e.g. Somali) have deep connections with more familiar tongues such as Arabic, but Semitic Ethiopian languages (e.g. Amharic) are much closer in historical distance. Third, there has been a fair amount of previous genetic analysis of these populations, and their synthetic character was obvious from those (e.g. mtDNA and Y results suggest a diverse array of haplogroups). What the AJHG paper reported was that the Eurasian ancestors of the Ethiopians admixed with the presumably Sub-Saharan indigenes ~3,000 years ago in a single pulse event, and, their closest modern relations in West Asia today are Levantines. To put a mild gloss on it the dating is controversial (using patterns of decayed genetic correlations of markers across the length of the genome). This is not just clinal variation. As I have notedif this dating of the admixture is correct then modern Ethiopians as a coherent biocultural entity post-date Egyptian civilization by thousands of years. During the reign of Hatshepsut, ~1500 BC, there was a trade delegation send to the land of Punt (probably Somaliland). The depictions of the people of Punt by the Egyptians were very strange, insofar as they did not look Sub-Saharan African, and, the queen of Puntland seemed to exhibit steatopygia more common among the Khoisan people. I posited speculatively that during this period of ancient Egyptian civilization East Africa was in ferment in regards to its population mix. The Bantu people who dominate the landscape of Sub-Saharan Africa east and south of Cameroon only began to expand in earnest after 1000 BC (reaching southern African about 1,500 years ago). It seems plausible that the range of Khoisan-like peoples was much further north and east than is the case today. Additionally, there are likely to have been other populations, currently uncharacterized, present on the landscape (it may be that the Khoisan loom large only because their distribution was such that relic populations survive to this day to be studied). The Tishkoff lab for example has a paper in preparation on the presumed Sub-Saharan African populations present in the Horn of Africa when West Eurasians arrived (the Sub-Saharan component of highland Ethiopians does not seem to be Bantu-like). I bring all this up again because Dienekes highlights an abstract by Joe Pickrell at next weeks' SMBE 2013: