Portal de Periódicos da CAPES

Hydrogen cyanide and phenylthiocarbamide sensitivity, mid‐phalangeal hair and color blindness in Yucatán, Mexico

1968; Wiley; Volume: 28; Issue: 2 Linguagem: Inglês

10.1002/ajpa.1330280217

1096-8644

Eugene Giles, Asael T. Hansen, John McCullough, Duane Metzger, Milford H. Wolpoff,

Hume's philosophy and hair distribution

Abstract Approximately 1450 persons, 800 of them unrelated, of both sexes from age eigth upward from the town of Ticul, Yucatán, Mexico, formed an American Indian (Maya) sample with apparently little Caucasian admixture for four genetic tests: ability to taste PTC and smell HCN, presence of mid‐phalangeal hair, and color blindness. A modified PTC sorting test indicated a nontaster allele ( t ) frequency of 0.29 in Ticul, a relatively high result for American Indians but compatible with previously reported Mayan data. A color vision deficiency frequency of 3.6% was found in the total male sample, and a subsample of unrelated males had a rate of 2.8%. No color blind females were detected. The Ticuleños exhibited a high rate of midphalangeal hairlessness, characteristic of American Indians, with a notable sex differential: 75.9% for males, 87.1% for females. Previous studies of the inability to smell HCN, most of which suggest an X‐linked recessive inheritance with an allele frequency of about 0.2, are reviewed. The Yucatán material, with a nonsmeller prevalence around 50% and no significant difference between the sexes, contradicts the X‐linked recessive hypothesis on the basis of both population and family analyses. No simple Mendelian scheme appears to fit the Ticul HCN sensitivity test results.