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In a recent study, scientists at Monell Chemical Senses Center report that genes play a large role in determining individual differences in sour taste perception. The findings may help researchers identify the still-elusive taste receptor that detects sourness in foods and beverages, just as recent gene studies helped uncover receptors for sweet and bitter taste.
Scientists have long known that sour taste is stimulated by acids in foods and beverages. However, it is still not completely understood how the taste system is able to detect and translate acidic molecules on the tongue into a neural signal that the brain perceives as ‘sour.’
In this study, researchers tested 74 pairs of monozygotic (MZ, identical) twins and 35 pairs of dizygotic (DZ, fraternal) twins to determine the lowest concentration needed for each twin to correctly identify a citric acid solution as ‘sour.’
Because MZ twins have nearly identical genes while DZ twins share only about 50% of their genes, more similar responses in MZ than DZ pairs suggests that genes help determine sensitivity to the taste in question. Responses were compared within the twin pairs, and then entered into a computer model to determine the relative contributions of genetic and environmental influences on sour taste sensitivity.
The models estimated that genes played a more important role than environment in determining individual differences in sour taste sensitivity, accounting for 53% of the variation.