SLC24A5 (solute carrier family 24, member 5) is a gene that is thought to explain around 25-35% of the difference in skin color between Europeans and Africans. The most common allele in Europeans has a single nucleotide polymorphism resulting in the change from one amino acid to another in the resulting protein.
The European allele produces a protein that doesn't work as well within the system that fixes melanin in the skin. That is as obvious as my face in the mirror, and I know it like the back of my hand. ;)
Seriously though, maybe the genome of some groups have adjusted to the need for lighter skin over the eons. That would be part of God's plan too.
Btw, your palm is on the front, or inside of your hand. The back of your hand is the part that tans, after all.
/just playing with ya, now. ;-)