Scientific American

Mounting evidence from genome studies indicates that, contrary to received wisdom, our species has undergone profound biological adaptation in its recent evolutionary past

New research raises the possibility that recent human history involved far more dynamic evolution than previously thought.
In Darwinian biology, the classic conception of natural selection is a “hard sweep,” in which a beneficial mutation allows some individuals to survive longer or produce more offspring such that eventually that variant becomes fixed in the population. In the early 2000s, when researchers were starting to look for signs of hard sweeps in the genomes of contemporary peoples, the clearest examples came from populations that had adapted to unique circumstances. For instance, around 42,000 years ago a selective sweep changed a protein on the surface of red blood cells in Africans to boost their resistance to malaria. People in the Tibetan Highlands underwent selective sweeps for genes that helped them tolerate low oxygen (intriguingly, populations of the Himalayas, Andes and Ethiopian highlands adapted to high altitude with different assortments of genes, taking different evolutionary paths to solve similar problems).