It took me a while to piece together how modern anthropologists handwaive away the differences between Europeans and Africans. They keep quoting the number that whites and blacks separated around 50,000 years ago, which is not long enough for significant changes to take place. However, part of our genes, perhaps the most important part, comes from Neanderthals. You'd expect the genes that would confer the best adaptation to the cold climate to make the most impact: genes for intelligence, planning, cooperation, and delay of gratification. The Neanderthals separated around 500 to 700kya and later interbred with early homo sapiens, around 50kya. That is, the genetic differences go back at least ten times further in time than they want to admit.