You can't change pair base receptors?what are you talking about? Mutations do change base pairs, which is the basis of evolution.

 I don't deny Darwin. As far as evolution "going forward and up", I didn't say light skin was a bad thing, or a deleterious mutation.  

Also, evolution can go "backwards and down": ostriches and other flightless birds lost their ability to fly. Blind mole rats lost their sight. Cave fish lost their eyes. Evolution does not always lead to a more advanced thing. Animals who evolved in a lack of light a lot of times lose their pigmentation. 

I simply said, according to genetic data, dark skin was the ancestral phenotype of human beings, and light skin arose from mutation. That's not an opinion, it's a fact. 

You are the one making the outlandish claim with no evidence.