Repeated evolution: Lactose tolerance arose independently in Africans and Europeans


In January 2007, an international team of researchers led by geneticist Sarah Tishkoff announced that they had uncovered the genetic roots of Africans’ lactose tolerance.

Just as in Europe, on this continent, mutations (in this case, probably three) randomly arose, and these happened to have the effect of keeping the lactase gene switched on.

https://evolution.berkeley.edu/evolibrary/news/070401_lactose