Because our species started in Africa 200,000 years ago but didn’t leave Africa until bout 60,000 years ago — and then only few hundred of them — then mutations to Africans’ genes — to good, bad and neutral effect — have accumulated far more often than in those of us in Asia and Europe who are descendants of the original emigrants.
Because of the large number of mutations in every one of Africans’ 20,000 genes, then they have disproportionately taller individuals than we do. They also have disproportionately shorter people we do, too. It means that, in many sports requiring great physical skills and co-ordination, Africans are always among the winners. Or at least they seem to be in some sorts in the Olympic Games.
It also means that, because mutations — good, bad and neutral — can occur in brain genes as well as in muscle genes — then Africans ought also to be capable of great intellectual feats and become superior to us in some disciplines. So they might be, once enough of them have had enough experience in Western type education. Some economic historians, such as Deirdre Nansen McCloskey think that this may turn out to be the case.
However, some back of an envelope maths is in order here. Although only a few hundred humans left Africa 60,000 years ago their numbers have expanded enormously since then to literally billions. Because mutations occur at a constant rate every generation then the number of mutations that have occurred in non-African man in the last 60,000 years must be approaching the number that African man has acquired in the last 200,000 years.
This suggests to me that the average number of mutations of non-Africans is any fairly large region — if not in the world as a whole — a figure that won’t be known for several years yet — is probably similar. However, intellectual attainment — and inn ovative creativity — is not just about the number of good mutations of brain genes within any culture, but on the mental freedom within that culture.