GENETIC-CHARACTERIZATION OF THE CAYAPA INDIANS OF ECUADOR AND THEIR GENETIC-RELATIONSHIPS TO OTHER NATIVE-AMERICAN POPULATIONS

One-hundred sixty-four Cayapa Indians living in the Esmeraldas Provinc e (northwest Ecuador) were studied for several erythrocyte genetic mar kers (ACP1, ADA, AK1, CA2, ESD, GL01, G6PD, PGD, PGM1 subtyping and th ermostability, PGM2, SODA, and HB). The Cayapa show allele frequencies typical of those of South American Indians. The absence of the CA22, G6PDA, G6PD*A-, HBB*S, and HBB*C alleles and the low PGM1*1A and PGM 12A and high PGMI*1B allele frequencies indicate that very little (no more than 2%), if any, genetic admixture has occurred with the black community living in the same area. Correspondence analysis was used to study the genetic relationships between the Cayapa and other linguist ically defined Amerind populations and between the Amerinds and the ot her two native American groups, the Na-Dene and Eskimo-Aleut. The resu lts of this analysis, obtained on the basis of some erythrocyte and se rum markers and some blood group systems, show (1) the close affinity between the Cayapa and other South American populations, (2) the absen ce in the Amerind group of a clear-cut correspondence between linguist ic classification and genetic relatedness, and (3) the evident distinc tiveness of the Amerinds from other native American people.