CommentAry In Pursuit of taste Phenotypes

Notable progress has been made relating individual differences in bitter taste sensitivity to specific alleles and TAS2R recep-tors, but psychophysical evidence of reliable phenotypes for other tastes has been more elusive. In this issue, Wise and Breslin report a study of individual differences in threshold sensitivity to sour and salty taste, which, though failing to find clear phenotypes, exemplifies the type of approach and analysis necessary to disentangle sources of variance inherent in the psychophysical measures applied from those attributable to true differences in sensitivity. Methodological and theoretical lessons that can be taken from this work are discussed in the context of the early and dramatic evidence of chemosensory phenotypes that belied the complexity of taste receptor genetics and focused attention solely on peripheral determinants of sensitivity. Key words: genetics, individual differences, phenotypes, psychophysics, taste Experimental evidence of chemosensory phenotypes dates from a serendipitous observation in 1918 by the plant geneticist Albert Blakeslee. While classifying the colors of species of flowering plants, Blakeslee discovered that he and his assistant disagreed about which of 2 color variant