Digesting milk in Ethiopia: A case of multiple genetic adaptations

A genetic phenomenon that allows for the selection of multiple genetic mutations that all lead to a similar outcome - for instance the ability to digest milk - has been characterised for the first time in humans. The phenomenon, known as a 'soft selective sweep', was described in the population of Ethiopia and reveals that individuals from the Eastern African population have adapted to be able to digest milk, but via different mutations in their genetic material. A team of geneticists from UCL, University of Addis Ababa and Roskilde University have shown that five different alleles are found in the Ethiopian population that cause adult lactase production, one of which is newly confirmed. Their study is published in The American Journal of Human Genetics . Professor Dallas Swallow, from the Department of Genetics, Evolution and Environment, senior author of the paper said: "Our genetic make-up determines our ability to digest milk into adulthood. Just over a third of the global population have inherited genes that allow us to make lactase, the enzyme that digests milk, as adults. "This study shows that several different genetic changes that allow our bodies to make lactase have emerged independently.