The work builds on a previous study by the group, which explored the evolutionary history of a gene called TAS2R38, responsible for the ability to perceive the bitter tasting compound PTC. In that research, published in Molecular Biology and Evolution in 2011, the geneticists discovered that something other than taste perception must have driven the selection of that gene.
The current work examines the related gene TAS2R16, which codes for a molecular receptor that binds salicin. Salicin is a chemical found naturally in willow bark, the source of aspirin. It acts as an anti-inflammatory but in large doses can be toxic. It is also found in many nuts, fruits and vegetables.
To understand the patterns of variation at TAS2R16 in humans globally, the researchers collected DNA from 595 people in 74 populations across Africa with diverse lifestyles, such as pastoralism, hunting-gathering and agriculture. They sequenced the stretch of DNA encompassing the TAS2R16 gene in all of these individuals and also examined previously collected DNA from 94 non-Africans from the Middle East, Europe, East Asia and the Americas and found 15 variants total, most of which were only found in Africa.
In addition, the researchers asked 296 of the Africans sampled to perform "taste tests" of progressively more concentrated solutions of salicin and report when they could detect a bitter taste. The team also performed a cellular analysis, led by Integral Molecular scientists, to see the molecular effects of different TAS2
|Contact: Katherine Unger Baillie|
University of Pennsylvania