Red Flower Publications

Abstract

Phenylthiocarbamideor PTC (or Phenylthiourea) is a chemical compound which has the ability to categorize people into two classes, tasters and non-tasters irrespective of age, sex and race (Fox, 1932). Blakeslee and Salmon (1935) concluded that the taste sensitivity (to PTC) is controlled by a single pair of autosomal gene ‘T’ and ‘t’ with tasting ‘T’ gene being dominant over non-tasting ‘t’ gene. Inability to clearly identify different colours of the spectrum is widely known as colour blindness. The difficulties can be mild to severe. Colour blindness exhibits a sex-linked inheritance.

A study of taste sensitivity to PTC and incidence of colorblindness was conducted among two population groups- Rajputs and Bhils- of Sirohi district, Rajasthan. A total of 230 individuals were studied among which Bhils constituted 128 individuals (59 males and 69 females) and Rajputs constituted 102 individuals (60 males and 42 females). The method of serial dilution as given by Harris and Kalmus (1949) was used for testing taste perception. Colour- blindness was examined with the help of Ishihara (1960) plates numbered 1 to 25 in a room with sufficient daylight. The frequency of non-taster‘t’ gene was found to be higher in Rajputs (0.524) than in Bhils (0.405). The frequency of color blindness is low in the Bhil population(1.56%) in comparison to the Rajput population (1.96%). The results have been compared with the populations of North and West India. The incidence of colorblindness has also been studied in the respect to selection-relaxation hypothesis.