The ability to taste phenylthiourea (PTC) was tested among 1021 Quechua-speaking subjects from the Central Highlands and Eastern Lowlands, and 864 Mestizo subjects from the Eastern Lowlands of Peru. In addition, 1137 Quechuas and 873 Mestizos were tested for the frequency of tongue rolling and right hand/left hand clasping. Among the lowland Quechua Indians and lowland Mestizos the frequency of non-tasters equals approximately 6.8% for both groups, while for the highland group it equals 3%; it is suggested that the similarity in non-taster frequency between the lowland Quechuas and Mestizos may reflect the common environment. The frequency of tongue rolling is greater for the Mestizos (65%) than for the Quechuas (53%). The frequency of right hand clasping does not show any differences between the three populations.
Frisancho, A Roberto; Klayman, Jane E.; Schessler, Teryl; and Way, Anthony B.
"Taste Sensitivity to Phenylthiourea (PTC), Tongue Rolling, and Hand Clasping Among Peruvian and Other Native American Populations,"
2, Article 7.
Available at: https://digitalcommons.wayne.edu/humbiol/vol49/iss2/7