Analysis of ? S and ? A genes in a Mexican population with African roots

To investigate the origin of the ? A and ? S genes in a Mexican population with African roots and a high frequency of hemoglobin S, we analyzed 467 individuals (288 unrelated) from different towns in the states of Guerrero and Oaxaca in the Costa Chica region. The frequency of the sickle-cell trait was 12.8%, which may represent a public health problem. The frequencies of the ?-haplotypes were determined from 350 nonrelated chromosomes (313 ? A and 37 ? S). We observed 15 different ? A haplotypes, the most common of which were haplotypes 1 (48.9%), 2 (13.4%), and 3 (13.4%). The calculation of pairwise distributions and Nei's genetic distance analysis using 32 worldwide populations showed that the ? A genes are more closely related to those of Mexican Mestizos and North Africans. Bantu and Benin haplotypes and haplotype 9 were related to the ? S genes, with frequencies of 78.8, 18.2, and 3.0%, respectively. Comparison of these haplotypes with 17 other populations revealed a high similitude with the population of the Central African Republic. These data suggest distinct origins for the ? A and ? S genes in Mexican individuals from the Costa Chica region. Zapotitlán 2002 Elsevier Science (USA)