Colour-blindness and sensitivity to PTC in Hadza.

211 Hadza (Tanzania) males, including members of both western and eastern groups, were tested for red-green colour blindness with the Ishihara non-numeral plates. Three closely related individuals were considered to be protanopes. It is possible that they received the gene from an Isanzu ancestor. 118 individuals (both sexes) were tested for taste-deficiency to PTC using a single solution and a sorting test. 22% of the males and 27% of the females were considered to be non-tasters. Since this appeared to be a high figure for an African population a sample of 53 eastern Hadza males was later tested using solutions 1, 3, 5, 7, 9, 11, 13. A conservative interpretation of the threshold distribution gave an estimate of 43% non-tasters. Corrections were applied for the inclusion of close relatives in the samples. The results are discussed in relation to other African data.