Genetic study of phenylthiocarbamide (PTC) taste perception among six human populations of Jammu and Kashmir (India)

Abstract

Background: The ability to taste phenylthiocarbamide (PTC), a bitter chemical has long been known to be a bimodal autosomal trait inherited in a simple Mendelian recessive pattern which is being widely used for both genetic and anthropological studies. The frequency of taster and non-taster allele is found to vary in different populations. The present paper deals with the distribution of PTC tasting ability as a marker to study the genetic structure among Muslim populations of Jammu; as no detailed information is available.
Aim: To investigate the prevalence and gene frequencies of PTC taste sensitivity among male and females.
Subjects and methods: We have undertaken a survey of gene frequencies of PTC taste ability for six different endogamous groups including tribal population. PTC serial dilution method was used to assess the PTC taster and non-taster phenotypes. Hardy–Weinberg method was used to determine allele frequencies.
Results: Gujjar and Bakarwal population showed highest PTC threshold while Syed had the least. The phenotypic frequency for PTC taste ability varies within six populations; Syed were observed with highest taster frequency while Gujjar and Bakarwal had lowest taster frequency. The taster frequency of six different populations showed that the percentage of taster frequency was more frequent than that of the non-tasters. Also, females (x²= 4.563, df =5, p= 0.471) had more PTC tasters than males (x²= 5.254, df =5, p= 0.385), being statistically significant. The allelic frequencies in Gujjar and Bakarwal for non-taster (t) males and females were 55.86 and 54.55, respectively. In Syed population, t-allele frequencies for males and females were 45.75 and 37.79, respectively, while the other four populations showed intermediate t-allele frequencies. The heterozygosity showed little variation among all of the six populations.

Keywords: Phenylthiocarbamide (PTC); PTC threshold; Gene frequency; Genotype frequency; Heterozygosity; Human population