Do you believe in evolution and genetics? Different races have various different afflictions, sickle-cell, tay-sachs, cancer rates, etc. Different facial structure, average height, body fat distribution, muscle mass, limb length, etc.

You would have to deny evolution and genetic inheritance to think that different groups of people living apart for tens of thousands of years in vastly different environments didn't result in selection via external forces to better survive in those environments. Just look at the body type difference between an eskimo and a sub-Saharan african.