Do you think about your own skin? I think about it every day. Everyone, including me, looks in the mirror and says, “Hmmm, getting a bit older.” I see it as my autobiography. My skin has seen everything that I have, all of the weather, the sorrow, the happiness, the toil. I love the changes that I see in my skin, and I see it as part of my human story. What about skin color? Why does this interest you as a scientist?

It is one of the most fundamental ways in which people vary in their appearance. People have also made a big deal about skin color. It’s caused humanity a lot of difficulties because people have associated color with the value of human character and moral values. Do we know when dark skin first evolved in our ancient ancestors in Africa? We can make a very good estimate from the fossil record, as well as from studies done by human geneticists. Humans probably evolved naked…