"The takeaway message here, as Jablonski points out, is that there is no such thing as different races of humans. Any differences we traditionally associate with race are a product of our need for vitamin D and our relationship to the Sun. Just a few clusters of genes control skin color; the changes in skin color are recent; they've gone back and forth with migrations; they are not the same even among two groups with similarly dark skin; and they are tiny compared to the total human genome. So skin color and "race" are neither significant nor consistent defining traits. We all descended from the same African ancestors, with little genetic separation from each other. The different colors or tones of skin are the result of an evolutionary response to ultraviolet light in local environments. Everybody has brown skin tinted by the pigment melanin. Some people have light brown skin. Some people have dark brown skin. But we all are brown, brown, brown."