Genetic analyses of sweet taste transduction

A genetic analysis of sweet taste transduction was initiated using fruitflies and humans. In flies, behavioral and receptor cell electrophysiology data indicate different mechanisms for fructose and glucose in or before the receptor cells. Fructose nontasters (FN) and glucose nontasters (GN) were selected from natural populations of adults and larvae. The FN are the first fructose taste variants isolated in any species. There were no significant differences between male and female frequencies for either variant type, and no observable differences in banding patterns between wildtype and FN X-chromosomes. These and preliminary cross-breeding data suggested a polygenic trait, either completely autosomal, or including coding by a defective X-chromosomal gene for which an autosomal gene(s) can compensate. In humans, psychophysical functions also indicated different fructose and glucose mechanisms. Variability analysis suggested separate signals for the monosaccharides and an additive sucrose signal. Potential GN were identified by elevated glucose thresholds. © 1997 Elsevier Science Ltd