The reductionist ideology, according to which genes directly determine the qualities and behaviour of individuals and human societies remains widespread. It explains the puzzlement of many when confronted by the news that human beings have no more genes than an ass or ox, and far less even than a toad.
The same kind of prejudice lurks behind the sensational, unscientific announcements claiming that science has identified the genes controlling intelligence, aggression and many other mental characteristics.
The connection between such persistent ideologies and racism is obvious: it is easy to imagine the devastating effect on populations often predisposed to believe in the omnipotence of the gene by the simultaneous announcement that scientists have located a region on the chromosome linked to intelligence and that this region varies in form according to the different ethnic groups.
The fact that people the world over are to a large extent genetically homogeneous, as confirmed by study of the genome, is unfortunately not sufficient to avert the threat of biology taking a racist turn. There are two kinds of reasons why this is so.
Firstly, the combinatory nature of the effect of genes means that very slight differences can have far-reaching consequences for living beings. Secondly, the assertion that racism is illegitimate since races do not exist at the biological and particularly genetic level is tantamount to acknowledging that, if they were to exist, racism would be tolerable. However, this is in no way the origin of racism nor the justification for anti-racism.
It is true that human races do not exist in the sense in which we talk of different races of animals. All human beings are in fact highly homogenous genetically since our common ancestor — who lived 200,000 years ago at the most, in Africa — is young in terms of the evolution of life. All the continents seem to have been populated by groups of peoples who left Africa some 70,000 years ago....