The most critical factor regarding light skin in the North and Vitamin D synthesis and absorption is the development of rickets with the lack of adequate Vitamin D. Without enough D, the pelvis does not develop well, and childbirth becomes difficult if not impossible. Thus gentlemen instinctively prefer blonds and well developed hips, because such women are much better able to give birth to live children. And thus the gene spreads rapidly. Also, avoiding dinosaurs was never a factor for humans.
I think race is simply an environmental mutation. It’s nothing more than humans being molded to their environment. Natural environment determines race. Every single difference between humans from skin color to nostril size to hair type is an adaption.
If you change a person’s environment, deprive them of technology and knowledge of their past, after enough millenia, their race will change. If this had widespread acceptance, racial strife would end because when a white looks at a black or vice versa, they will see themselves.
And this white skin re vitamin D doesn't take into consideration the Asians and Asian sub categories, re those who have lived in northern, COLD places, for many millennial.