r b c the r b c in sardinia is m a clade that is absent in all sub saharan and other african populations it was only detected in lebanon sardinia and corsica its ancestral clade is v and v clades are most common in sub saharn africa but r b v itself is not sub saharan due to its ancestor p ancestor of both v and m is not sub saharan african but from the eastern eurasia where in turn its ultimate ancestor m r b r a derives from thus before r b p v entered sub sahran africa from eurasia neareast it must have split into subclade m and moved along the mediterranean as for the distribution of v clades in sub sahran africa cruciani et al in summary our data indicate a significant male contribution from northern africa and ultimately asia to the gene pool of the central sahel the trans saharan population movements resulting in this genetic pattern would seem to mirror the spread of the proto chadic languages and most likely took place during the early mid holocene a period when giant paleolakes may have provided a corridor for human migrations across what is now the sahara desert cruciani et al note the complete absence of m in africa table