FLICKR, BBUMMost adult mammals can’t digest milk, but humans have evolved lactase persistence—the continued activity of the lactose-digesting enzyme lactase—several times, independently and in different parts of the world, during the last 10,000 years. Evolutionary biologists have proposed several theories to explain the strong selection for lactase persistence among dairy-consuming populations, but to date, none have provided definitive reasoning for the evolution of such an unusual digestive ability.
Analyzing ancient DNA from the skeletal remains of eight late Neolithic Iberian people, scientists now present evidence to suggest that one such hypothesis—that lactase persistence was selected for among early northern Europeans to allow people to drink milk to avoid calcium and vitamin D deficiencies—could not alone explain the rapid rise in lactase persistence across the continent. Their work was published in Molecular Biology and Evolution today (January 22).
“It is likely that the advantage provided to lactase-persistent individuals was not constant throughout time and space,” University College London’s Pascale Gerbault, whose own work focuses on the spread of lactase persistence in Europe but was not involved in the work, told The Scientist in an e-mail. The new study “may provide some support for this ...
