I think the subject of race has been so difficult and so polluted by malign ideas that most people have just left it alone, including geneticists. ... Most genetic variation is neutral – it doesn't do anything for or against the phenotype, and evolution ignores it – so most previous attempts to look at race have concluded that there's little difference between races. I think this position is the one on which the social scientists are basing their position. ... If you look at the genes that do make a difference, selected genes, which are a tiny handful of the whole, you do find a number of differences, not very many, but a number of interesting differences between races as to which genes have been selected. This, of course, makes a lot of sense, because once the human family dispersed from its homeland in Africa, people faced different environments on each continent, different climates, different evolutionary challenges, and each group adapted to its environment in its own way.