ACTUALLY they don't.
In the northern areas, it is better to have whiter skin because your skin can easily absorb vitamin D, for there is less sun in the northern areas of the earth.. The light eyes and hair is caused by the less melanin, so it is better to have those traits in that kind of area.
black people need darker skin because they are near the equator or in a hot sunny area, so they need to protect themselves from that. Black people have more chance of not getting enough vitamin D in the northern areas. That can cause multiple diseases.
Also, white people in sunny areas are more likely to get skin cancer, but they are more likely to fight it off.
black people are less likely to get skin cancer, but when they do get skin cancer it is extremely hard to fight off.
so it's a switch off.
best traits match their locations on the earthh...
@Kakkaboo not true or fact at all. whites can stay in a long time in the sun. blacks slowly deterriorate their bones not getting enough vitamin D in the northern part of Earth.
dominate gene does not mean superior. If you actually LEARNED genetics you would know this.
The reason why light skinned blacks are birthed from black parents is because of the white recessive genes in both parents. Therefore, the "superior" recessive white gene tends to take over in so-called "black" Americans.