In short, as far as biological science is concerned, there are no general physical determinants that line up with each of the major races. The mapping of the human genome in the early twenty-first century yielded no data about race. Scientists have in the past differed on where to draw the line between races, coming up with anywhere between three and sixty human races. There is no single gene that determines a person's race, and the combinations of genes that are more frequent in each of the major racial groups are not present in all members of those groups. However, if by the term race we mean a system of human types that differ in objective physical ways that scientists can study, this system has no foundation in biology. People think that race must be biological because members of different races have different physical traits that they inherit from their parents, and biology includes the study of heredity. Instead, skin color can be used as shorthand for the idea of race as a system of biological human types. Skin color does have a lot to do with race, but skin color differences aren't socially neutral variations in the same way that differences in hair or eye color often are. It is provocative to refer to race simply in regards to skin color. Obama's skin hue could be identical to that of a white person who has a suntan, but calling Obama “sun-tanned” disregards an ancestry and self-identification that has resulted in his African American identity. In 2008, when Italy's Prime Minister Silvio Berlusconi referred to President Barack Obama as “sun-tanned,” Italians and Americans considered it a racist gaffe.

More than skin deep