If you take your coffee without sugar or your pancakes without syrup, chances are you've got some European ancestry in your blood. New research reveals that people whose early relatives lived in Europe are more sensitive to sweet tastes than those whose ancestors came from other parts of the world.
Scientists led by Alexey Fushan of the National Institute on Deafness and Other Communication Disorders in Bethesda, Maryland, asked 144 people from various ethnic backgrounds to rank the sweetness of nine solutions ranging from 0% to 4% sugar. The volunteers' sucrose sensitivity turned out to be strongly associated with two variants of a gene called TAS1R3, which plays a major role in encoding the main carbohydrate sweet taste receptor.
Consulting a reference collection of DNA from 1050 people from around the world held by CEPH, the French gene database, the scientists found that most Europeans have both of the sweetness-sensing variants. The variants are less widespread in people from Asia and the Middle East and are least prevalent in Africans, the team reports in the 11 August issue of Current Biology.
Co-author and geneticist Dennis Drayna says the disparity may be evolutionarily significant. "People who study diet and evolution have pointed out most of the high sugar–containing plants like sugarcane are tropical plants," he notes. "So in northerly latitudes, you have to be more sensitive to sugar to find calories." Molecular biologist Stephen Wooding of the University of Texas Southwestern Medical Center at Dallas agrees that the difference may be adaptive. But he says the particular adaptation isn't yet clear.