Genetical Differences in Taste Sensitivity to Phenylthiourea and to Anti-thyroid Substances

Abstract

FOX¹ first observed that people differed in their ability to taste phenylthiourea, and it was found (Blakeslee and Salmon², Blakeslee³, Snyder^4,5) that these differences were genetically determined. The distribution of taste thresholds to this substance in all populations so far studied has been found to be bimodal. Familial investigations indicate that the two classes of individuals, tasters and non-tasters, that is, those relatively sensitive and those relatively insensitive to phenylthiourea, differ in respect of a single gene pair, the tasters being homozygous or heterozygous for the dominant allele, the non-tasters homozygous for the recessive allele. Between one quarter and one third of all individuals tested in various populations appear to fall into the recessive class. Fisher, Huxley and Ford⁶ have described observations which suggest that similar differences may exist among anthropoid apes. They have pointed out that this implies the existence of a stable, balanced polymorphism, and that, for such a system to occur, the heterozygotes should have had some selective advantage over the two types of homozygotes.