Human evolution. There's more than one way to have your milk and drink it, too.
Gibbons
Ann
A
D000349:Africa; D000818:Animals; D044383:Black People / Q000235:genetics; D002417:Cattle; D004063:Digestion; D005006:Ethnicity / Q000235:genetics; D005060:Europe; D019143:Evolution, Molecular; D006801:Humans; D043322:Lactase / Q000235:genetics* / Q000378:metabolism; D007785:Lactose / Q000378:metabolism*; D008892:Milk / Q000378:metabolism*; D009154:Mutation; D012641:Selection, Genetic; D013995:Time; D044465:White People / Q000235:genetics
D043322:Lactase; D007785:Lactose