Well then perhaps you can provide the color they improved upon or, really, since they are DNA improvements, the sequence they improved.
Sure.
Dark skin is ideal for Africa and other equatorial areas. The Mediterranean had a different climate, so people in that area have a lighter skin color with tanning ability to provide a better adaptation between protection from ultraviolet radiation (dark skin--summer) and production of vitamin D (light skin--winter). Farther north skin colors are lighter still, reflecting adaptation to still less intense ultraviolet radiation and the need for more vitamin D production. These topics are well discussed in books on human races and adaptation. You should check out a few. I can provide references if you really are interested.
As for DNA sequences, talk to the genetics folks.