My favorite example of a (real) recent selective pressure is lactose tolerance, which is well-correlated with ancestry in regions that a) are prone to vitamin D

My favorite example of a (real) recent selective pressure is lactose tolerance, which is well-correlated with ancestry in regions that a) are prone to vitamin D deficiency (Northern Europe especially) and b) regions that have cows or sheep, regardless of sunlight. So in particular most of Africa is lactose-intolerant, but many pre-modern West African groups were pastoral herders and can digest lactose. It is a bit of a mystery how this happened: other lactose-intolerant groups still used milk to make yogurt and cheese with much less lactose, and it’s not clear why there would have been pressure for adults to drink raw milk - perhaps a water-borne disease caused a bottleneck? See epidemiology here: https://en.wikipedia.org/wiki/Lactose_intolerance https://en.wikipedia.org/wiki/Lactose_intolerance