That sounds like a hypothesis that brown folks migrated north and evolved to be light as opposed to "light skinned peopled moved to the north". The latter is the historically accurate situation.
> That sounds like a hypothesis that brown folks migrated north and evolved to be light as opposed to "light skinned peopled moved to the north". The latter is the historically accurate situation.
Wait, no, that's inverted. Our ancestral state out of Africa was dark skin and we evolved light skin when we were no longer subject to the UV pressures there. It makes sense to me since the advent of light skin is quite recent in our species, and the darkest skin requires a bunch of pigmentation genes to be set just right, so random mutation can easily produce lowered pigmentation, so adaptation to the Vitamin D pressure would have been quite possible. I remember looking at this ages ago and it was pretty well-known at the time but I just took a second look and it seems it is still quite established though the advent of light skin among humans is not as smooth as previously thought: https://www.anthropology.net/p/the-evolution-of-european-pig...
Just in a smell-test way, we'd have had to sustain these lighter skinned populations under intense UV selective pressure for a long enough time for them to migrate North out of Africa. That just sounds unlikely on its own.
Wait, no, that's inverted. Our ancestral state out of Africa was dark skin and we evolved light skin when we were no longer subject to the UV pressures there. It makes sense to me since the advent of light skin is quite recent in our species, and the darkest skin requires a bunch of pigmentation genes to be set just right, so random mutation can easily produce lowered pigmentation, so adaptation to the Vitamin D pressure would have been quite possible. I remember looking at this ages ago and it was pretty well-known at the time but I just took a second look and it seems it is still quite established though the advent of light skin among humans is not as smooth as previously thought: https://www.anthropology.net/p/the-evolution-of-european-pig...
Just in a smell-test way, we'd have had to sustain these lighter skinned populations under intense UV selective pressure for a long enough time for them to migrate North out of Africa. That just sounds unlikely on its own.