Common Worldwide Variation Discovered In Human Taste Receptor Genes
Background: Differences in our sense of taste may have a profound impact on which foods we choose to eat, so it is important to understand the basis of these differences. Recent advances in chemosensory science have led to the identification of taste receptors, located on the surface of taste cells that reside on the taste buds on the tongue. These receptors bind to tastants released from food and initiate signals to the brain, where the specific taste is recognized. It has been known that the T2R gene family is involved in detecting bitter taste in humans. This gene family contains 25 different genes, encoding different receptors that allow humans to taste a wide variety of different bitter substances.
Advance: In studying the individual difference in bitter taste sensation, NIDCD intramural scientists discovered that all 25 human bitter taste receptor genes exist in a variety of different forms in the population. These genes encode for different receptor proteins. Evolutionary genetic analyses suggest the different forms of these genes have occurred in high frequencies in the population under the influence of natural selection. This implies that the different forms of each receptor functions to sense different bitter substances. Given the many different forms of each receptor discovered, it is clear that each person is endowed with an almost unique set of bitter-sensing abilities. In addition, for some bitter receptors, different forms are found to be present at higher frequencies in different populations.
Implications: These findings reveal how inherited factors affect taste perception and food preferences in different individuals. These preferences can have major implications for dietary choices each person makes. Obesity and Type 2 diabetes are known to be caused by a combination of genetic and environmental factors. The variations found in taste receptor genes may represent a portion of the underlying causes of these disorders, and additional research is warranted. In addition, the discovery that different forms of a particular gene exist at high frequency in different populations may provide information about ethnic differences in food preferences and dietary choices, and may allow reveal more about health disparities between different groups of individuals.
Citation: Kim U, Wooding S, Ricci D, Jorde LB, Drayna D.Worldwide haplotype diversity, and coding sequence variation at human bitter taste receptor loci. Human Mutation 26: 199-204, 2005.
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