PhoenicianRomans You are correct, I was wrong about the evolutionary benefits of dark skin and light skin.

Given that his brother is color-blind (red-green), this is all the more amazing.

I vaguely remember having heard that there are 16 different alleles for color vision and the variation is all over the lot. As a friend of mine said: “Some people have more crayons in their box.”

Which black folk under which circumstances? Seafood is a source of vitamin D; people with a heavy seafood diet have less selective pressure for fairer skin. It’s the darker skinned away from the coast that would suffer the most.

And I suspect that you’re wrong about the benefits of black skin in evolutionary terms. Granted, it is not a fool-proof or perhaps even a great protection from the sun, but it is *some* protection, and the problem would have been ongoing for pre-industrial peoples. There would have been a continual selective pressure against fair skin for people in the tropics.

Which black folk under which circumstances? Seafood is a source of vitamin D; people with a heavy seafood diet have less selective pressure for fairer skin. It’s the darker skinned away from the coast that would suffer the most.

And I suspect that you’re wrong about the benefits of black skin in evolutionary terms. Granted, it is not a fool-proof or perhaps even a great protection from the sun, but it is *some* protection, and the problem would have been ongoing for pre-industrial peoples. There would have been a continual selective pressure against fair skin for people in the tropics.

Brad, the Y chromosome isn’t just a shorter version of the X chromosome with some information left out. The Y chromosome contains hormone production genes to trigger male fetus development, and some others that are used in sperm production. That’s it.

That means any gene on a male’s X chromosome will be unmatched on the Y chromosome. Hence the load of recessive genes that express far more often in males. (MPB, red-green colorblindness, etc.)

They also wouldn’t be mistaken for Swedes or Norwegians, which is what most people think of when they’re thinking of light-skinned northern Europeans. When I talk about “light-skinned” people, I’m talking about blond, blue-eyed people with light skin, or redheads with pale skin.

If your definition of “light-skinned” includes Mediterranean people from southern Italy, Spain, or Greece then, yes, by your definition, the Inuit and similar peoples are “pretty light-skinned.” When comparing them to other northern peoples like the Scandinavians, though, they’re distinctly darker.

Please note that in this discussion of “light-skinned” and “dark-skinned,” I am not making any value judgement whatsoever on which color of skin is “better” to have, or if people with one skin color are “better” than another. We’re talking about how humans adapted to the environments they found themselves in over the millions of years that we developed. Nothing more.

And you should probably let the National Institutes of Health know that they’re spreading misinformation when they advise dark-skinned people living in northern states to take vitamin D supplements. I, too, would be interested in seeing journal articles refuting those studies.

Do you have a link to that? The paper I like to refer to was published in 2000, so it might well be out-dated, but I haven’t discovered anything newer on the topic in my usual reads.