Twin boys inherit different genetic codes from mother

Twins Kayden and Layton Richardson

A mother in London had twin boys, both of whom were born white, but one has gotten darker as he's gotten older (Kayden), while the other boy (Layton) has gotten lighter. The mother is of mixed race, with a Nigerian and English background, while the father is white. This is a rare genetic occurence according to experts at Oxford University, because genes usually mix colors together, rather than keep them separated. In this case, it seems the genes didn't combine and were passed on as separate genetic codes.