From The Economist:

James Watson: A pioneering biologist is reprimanded for unscientific, offensive views

A great career comes to a sad end

Print edition | Science and technology, Jan 17th 2019

… Dr Watson’s views about race and intelligence seem to stem from his keen interest in “The Bell Curve”, a book published in 1994 by Charles Murray and Richard Herrnstein, that, among other things, argued African-Americans were less intelligent than white Americans and genetic differences between ethnicities played a role in the difference. Modern genetic research has largely discredited these ideas.

Biologists know that there is a substantial genetic component to intelligence. Depending on the precise measure of intelligence being studied and the statistical model being used, it can range anywhere from 20-60%. And observational research from the 1980s, cited by the authors of “The Bell Curve”, showed that, if you ask people to self-identify on the basis of ethnicity and then measure their mental performance in some way, for example iq or the number of years in education, you will find differences in the mean attainment levels between different groups.

Genetics, however, cannot be the main reason for any observed differences, says Ewan Birney, director of the European Bioinformatics Institute, in Cambridge, because self-identification of ethnicity does not easily map onto genetic ancestry. “African-Americans have a substantial amount of European genetic ancestry—you should in fact call them ‘African-European-Americans’,” observes Dr Birney.