Genetic basis for taste variability in human bitter perception

DRUNDAY, F.; PORRETTI, J.; CALVIÑO, A.M.

Instituto de Biología y Medicina Experimental, Buenos Aires

Jornada; VIII JORNADAS MULTIDISCIPLINARIAS DE LA SOCIEDAD ARGENTINA DE BIOLOGÍA; 2006

Sociedad Argentina de Biología

There are individual differences on bitterness of 6-n-propyl-thiouracil (PROP) which is perceived very, medium or less bitter by supertasters (ST), taster (T) or non taster (NT), respectively. Previous results with a variety of psychophysical tasks showed that approximately 60% of the individuals received a reliable phenotypic tipification while the remaining exhibited much variability. This study was undertaken to analyze this variability by means of bioinformatic resources (ClustalX and Phylip package). 36 gene sets obtained from GenBank and Expasy were analyzed. From these, 25 were intact bitter taste receptor genes (hTAS2R, G-protein-coupled receptors). Several possible subfamilies emerged from the phylogenetic tree obtained for this multigene family.  By means of map view data visualization tool it was found a cluster of independent genes (hTAS2R43 to 50) located near hTAS2R13 and 14, giving a subfamily with high similarity in chromosome 12.  Another clusters included hTAS2R38 in chromosome 7 and the hTAS2R1 in chromosome 5.  SNPs taken from NCBI (databaseSNP) showed high SNP frequency/gene (mean value = 0.50%) from 0% (hTAS2R41, 43, 45, 47 without SNPs) to 1.94% (hTAS2R16).  The display of several subfamilies and the high number of polymorphisms in hTAS2R receptors gene support the poor performance of the psychophysical methods to obtain the phenotypic tipification in ST, T and NT individuals. These results suggest the possibility of replacing the tests which associate phenotypes and PROP sensitivity for tests which associate phenotypes and the TAS2R genotype.