It is no longer tenable to view West Eurasian back-migrations as limited events that affected only North and East Africa: their effects are clearly evident throughout Africa, having affected different populations to a different extent.A new paper in Science seems to confirm West Eurasian admixture related to Early Neolithic farmers throughout Africa, including the Yoruba, and Mbuti. I haven't read the paper yet, but it would be a striking discovery if confirmed.
UPDATE (1/26/2016). An erratum has now appeared that rejects the claim for Eurasian admixture in all Africans which was the result of the bioinformatic error. I continue to think that there was Eurasian back-migration into Africa, but it was a long shot that this had happened in the last 4,500 years (hence the ? in the title of this entry). A time series of African DNA may show whether the null model of Sub-Saharan Africans receiving virtually no admixture from Eurasia for the entirety of the existence of H. sapiens can remain valid.
Science DOI: 10.1126/science.aad2879
Ancient Ethiopian genome reveals extensive Eurasian admixture throughout the African continent
M. Gallego Llorente et al
Characterizing genetic diversity in Africa is a crucial step for most analyses reconstructing the evolutionary history of anatomically modern humans. However, historic migrations from Eurasia into Africa have affected many contemporary populations, confounding inferences. Here, we present a 12.5x coverage ancient genome of an Ethiopian male (‘Mota’) who lived approximately 4,500 years ago. We use this genome to demonstrate that the Eurasian backflow into Africa came from a population closely related to Early Neolithic farmers, who had colonized Europe 4,000 years earlier. The extent of this backflow was much greater than previously reported, reaching all the way to Central, West and Southern Africa, affecting even populations such as Yoruba and Mbuti, previously thought to be relatively unadmixed, who harbor 6-7% Eurasian ancestry.