Blood group, red cell, and serum protein variation in the Cabecar and Huetar, two Chibchan Amerindian tribes of Costa Rica

Genetic variation, using blood groups and red cell and serum proteins, was surveyed in the Cabecar of Chirripo and the Huetar of Quitirrisi, Costa Ric a. Thirty-nine loci were screened in a sample of 91 Cabecars and 40 loci in 45 Huetars. Twenty-seven loci were monomorphic in the Cabecar and 30 in th e Huetar. The proportions of polymorphic loci (P), out of 34 studied by ele ctrophoresis, were 0.235 and 0.177, respectively. Estimated gene diversitie s ((H) over cap) of the polymorphic loci were 0.050 in the Cabecar and 0.05 3 in the Huetar. Two polymorphisms, reported until now in Costs Rican and P anamanian Chibchan groups only, occurred at very high frequencies: TF*DGUA = 0.357 in the Cabecar, the highest frequency ever reported, and 0.033 in t he Huetar; and PEPA*F, which reached 0.26 in the Cabecar and 0.29 in the Hu etar. Nei's genetic distances and trees (two methods) were used to compare them to seven other Chibchan tribes of Costa Rica. The results placed both the Cabecar of Chirripo and the Huetar closer to the Talamancan Tribes (Bri bri and Cabecar). This was an unexpected result for the Huetar, since lingu istic studies suggested a closer relationship to the Guatuso. G(ST), D-ST, R-ST, and (D) over bar (m) for three Cabecar subpopulations (Atlantic, Chir ripo, and Pacific) doubled their values compared to estimates based on comp arison of only two subpopulations: Atlantic and Pacific. Total genetic dive rsity considering just the three Cabecar subpopulations resembled that obta ined including them plus six other Chibchan populations of Costa Pica. Am. J. Hum. Biol. 13: 57-64, 2001. (C) 2001 Wiley-Liss, Inc.