Very simple... Variety... Ever seen 2 very good looking people have kids... are all there kids good looking ?? No they are varied.
Why So many Ginger people in scotland ?? From strong genes hundered years ago, and as those genes have stayed in the same area and interbreed they have been subject to natural selection, also enviroment plays a huge role.
Go and live and bring up a huge family over 1,000 years on the african continent.. think you will be as white as you are now ?? Or could it be we where designed to adapt to the enviroment for our healths sake ?
Then what if like minded people take it upon themselves to stick together as they spread out in the earth, As they isolate themselves and breed etc you get a culture ???
I am from a branch of good looking well educated individuals that stuck together
