64% from (Sardinians/Basques) to Yoruba; this is difficult to interpret, but there has been evidence in the past that Africans and West Eurasians share more ancestry than Africans and East Asians do. In the linked post, I proposed a major episode of back-migration into Africa, and it is perhaps this that is being captured by this migration edge: Sardinians/Basques are the only two South-West Eurasian populations included, and any back-migration into Africa must have originated in the southern parts of West Eurasia.
Such a high level of back-migration may in fact be plausible, since Yoruba are a predominantly Y-haplogroup E bearing population, and the origin of the DE clade of the human Y-chromosome phylogeny is up in the air with both an African and Eurasian case having been advanced. Personally, I favor the Eurasian case, since within the CT clade, we have two subclades: CF (Eurasian) and DE (Eurasian/African).
Interestingly, John Hawks has recently discovered an unanticipated excess of "Neandertal ancestry" in Yoruba. This may also point to a back-migration into Africa and/or admixture of a group of Africans related to Eurasians (whom I've called Afrasians), with groups of Africans (Palaeoafricans) that split before the H. sapiens/H. neandertalensis common ancestor.
So, we should keep our minds open to the possibility that the greater similarity of West Eurasians to Africans is not the result of multiple Out-of-Africa waves, one of which affected only West Eurasians, but of an Into-Africa back-migration from West Eurasia.
Not necessarily European, Sardinians and Basques are probably the closest to the Eurasian element that may have contributed to the back-migration into Africa.
Well, we know that there is "Southern" (K7b) influence in North and East Africa. Henn et al. (2012) postulated substantial back-migration to North Africa and absorption of an indigenous "Maghrebi" component.
Yes, I think it is. The back-migration may have affected all of Africa, leading to the disappearance of the archaic forms as they intermixed with the back-migrants. The main difference between North and Sub-Saharan Africa, is that in the North they found Irhoud-like early H. sapiens, and in Nigeria they found Iwo-Eleru-like archaic forms.
I am very happy that Dienekes has arrived to these conclusions I have supported many times and so long ago. All this was synthesized in the Italian Refugium, in the migration of R1b1-V88 to North Africa by sea from North (Italy or Iberia), in the ancient presence of some of the most ancient hg. E in Sardinia (like the paper of Cruciani demonstrated), in the Eurasian origin of African languages, etc. etc.