We all came from Adam and Eve. Adam and Eve probably were medium-colored human beings. God built in their respective genes the different skin colors that humanity has now. Actually, we all have the same skin color, we only vary in the amount of the color we have.
Let AaBb stand for a person with medium skin tone. Let the capitals A and B stand for a black skin. Let a and b stand for light skin. Adam and Eve both had AaBb skin color. Adam ---AaBb. Eve---AaBb.
Based on the available genes they have, they could potentially bear children with different skin colors.
They could bear a son who has AABB skin color. This son would be very dark in color. Or they could bear a daughter with aabb skin color. She would be very light in skin color. Or they could have a child with BaAb skin color.
A human being with AaBb gene in him married to another person with the same genetic makeup could bear children with different skin colors over the long haul.
