Today, at the annual AAAS meeting, I attended a great talk by Nina Jablonski explaining very clearly and unambiguously why “race” (as in black, white, etc), is a complete myth. Interestingly, she noted that in the U.S. health agencies still use the concept of race — apparently because it makes everyone feel comfy, even though scientifically it has no meaning whatsoever.
I learned that Lucretius was apparently the first person to classify people by color. In his early work he was value neutral, but about ten years later he started associating personality with skin color.
But it seems that the real villian was Emmanuel Kant. He was the first to start ranking people, based on their skin color, from inferior to superior. Because he was a well regarded thinker, this nonsense was taken seriously.
The rest is history.
The key high order bit of the actual science is that dark skin is highly selected for in dry equatorial climates (where people with light skin tend to die off because UV-B from sunlight attacks their folic acid, which is necessary for proper embryonic development), whereas light skin is highly selected for far away from the equator (because absorbing some UV-B is necessary for vitamin D production, without which bones cannot grow properly).
Various populations have changed from dark to light and back again quite often over the last 70,000 years (when the first humans wandered out of Africa). For example, the ancestors of many people now living in southern India went from dark to light to dark again.
During the first 130,000 years of humanity’s existence, everyone lived in Africa. Genetic diversity during that time was vast, yet of course all those genetically diverse peoples were dark skinned because of selection for protection against UV-B.
Meanwhile, the light skin of caucasians and of east asians evolved via completely different mutations. In both cases, some genetic mutation arose that helped guard against deficiency in vitamin D — but implemented by unrelated genetic pathways.
So in reality, it’s all a tangle of genetically diverse subpopulations. Yet the U.S. we still indulge in the fantasy that there is something genetically meaningful about such words as “black” or “white”.