In a hundred thousand years or so? Evolution to me would be that where there’s almost a lack of sun the body would be black to absorb heat. Blacks are more susceptible to sunburn than whites. So basically what you’re saying is if Africans moved to a less sunlit area, say, Norway, eventually they’ll turn white, have blond hair and narrow noses? In a hundred thousand years or so.
Black skin, skin with higher melanin content, is more protected from the Sun than white skin. This is why melanin is also an inducible gene, laying in the sun increases the amount of melanin in your skin temporarily, to protect you from further exposure.
Yes, what I am saying is that a dark skinned population that moved to Norway (back in the day) would be under extreme selective pressure (caused by rickets) to accumulate less functional or less induced alleles of all the genes that put melanin into the skin.
How do you suppose a single human population derived such obvious differences, if not for natural selection of genetic variation?