Racists attempt to draw lines where no lines exist. The conclusion drawn by all relevant evidence of comparative anatomy, paleontology, serology and genetics is that all varieties of human beings have the same remote ancestry. The more we learn about prehistoric peoples, including the 'fossil men', the more we realize that mankind has always been characterized by great diversity. The 'pure races' are a myth. As far as evidence is available, it indicates that 'race mixture' has always been characteristic of mankind.
All peoples share so many fundamental similarities, despite superficial dissimilarities.
This is why scientists have difficulty in deciding where one so-called 'race' begins and another leaves off and this exposes the nonsense of the concept of 'racial purity' and the absurd doctrine of 'racial superiority'. No one group has a monopoly on genetic quality. Races are not static unchangeable entities but temporary dynamic eddies in a more or less continuous stream of cultural and physical change. Hence, 'race', which has no organic basis, is a category constantly being struggled over and remade across time by people in the same social class and differently at the same time by people whose class positions differ and is only given any meaning through the agency of human beings in concrete historical and social contexts which, according to Barbara J. Fields' essay, Ideology and Race in American History , makes race an 'ideological' category. That means that belief systems are vindicated by and masked by so-called 'biological' excuses.