Despite his frantic backtracking, James Watson's statement that Africans are less intelligent than Europeans follows a long and dubious tradition of geneticists claiming that supposed racial differences have a genetic basis.
Look, race has a genetic basis. At the most basic and simplistic level, the fact that black people are black and not white is because of a genetic difference, inherited genes that code for enhanced melanin production in the skin.
Thus there is a genetic basis to the single most obvious difference on which the whole concept of race is built. To deny that their might be other factors based on a genetic difference between races is just incredibly fucking stupid: it is a dangerous subsumation of science to political expediency.
There is a genetic basis to race: the concept of race is built on genetic differences. End of story. But, as Timmy emphasises, it isn't actually something that is necessarily important.
We can argue that race isn’t an important idea, that our common humanity (and indeed, the fact that variability within groups is almost always larger than that between group averages) means we should disregard it.
We can also argue that while some things are indeed racial differences and have a genetic basis, that the things that people think are (to be crude, dick size, or to be less so, sexual appetite, or in this case, intelligence) are in fact not.
But to claim that none of the observable differences between different groups of humans have a genetic basis is simply absurd.
Quite, and to observe a geneticist doing so, presumably in order to pander to the prejudices of his paymasters, is a very sad event for scientists everywhere.