Diversity of two short tandem repeat loci (CD4 and F13A1) in three Brazilian ethnic groups

Two microsatellites (CD4 and F13A1) were investigated in seven Brazilian populations: one group each of European- and African-derived subjects from Porto Alegre, southern Brazil, and five Amerindian tribes (three Tupi-Monde speaking [Gaviao, Surui, and Zoro], one Macro-Ge [Xavante], and one Carib [Wai-Wai]). For both markers, neo-Brazilians presented with a high diversity, but Amerindians showed a low level of variability. Genotype frequency distributions were heterogeneous among populations, the only exception being similar CD4 frequencies in Afro- and Euro-Brazilians. Gene diversity analysis revealed that most of the total variation is due to intrapopulational diversity in all populations, Because of the high information content of these markers in Afro- and Euro-Brazilians, these systems are most appropriate for forensic analyses. The comparison among Brazilian and other world populations revealed high similarity among populations of the same ethnic group, indicating a high discriminative power for these markers

Rare and Common Types of Phosphoglucomutase in two Brazilian Populations

PGM types were determined in 695 Whites and 1,032 Blacks from Porto Alegre, as well as in 38 Xikrin Indians of northern Brazil. Whites showed a higher prevalence of PGM21 than Blacks, the frequency of this marker being 0.26 among the Indians. No lack of heterozygotes was observed in this system, in disagreement with find­ings from two other reports. Two rare phenotypes were found, classified as PGM] 6-2 and PGM] 3-1. The Whites were all homozygotes for PGM12, its allele PGM22 showing a frequency of 0.01 among the Blacks and also occurring among the Indians, may be due to racial admixture. A “null” allele at this locus was also discovered as a result of an apparent maternity exclusion

Molecular Characterization of Glucose-6-Phosphate Dehydrogenase Variants from Brazil

Electrophoretic surveys of 7794 individuals from different regions of Brazil and a study of subjects with hemolytic anemia have disclosed 9 putative G6PD variants in addition to the B, A, A —, and Mediterranean types. No variants were found among the 3739 Brazilian Indians tested. Four variants underwent DNA analysis. Three were identified with the Mediterranean, Seattle, and Anaheim types, but the fourth variant was previously undescribed and we propose to designate it G6PD São Borj

High Frequency of CYP1A1*2C Allele in Brazilian Populations

The genetic variability of the CYP1A1 I462V polymorphism (CYP1A1*2C) was investigated in four Brazilian populations: three groups of African descent and one group of European descent. The CYP1A1 polymorphism was analyzed by two different procedures, first by the allele-specific polymerase chain reaction (PCR) method and then by the PCR–restricted fragment length polymorphism (PCR-RFLP) method before digestion with BsrDI. The frequency of CYP1A1*2C was 11% in Brazilians of European descent, a frequency that is slightly higher but not statistically different from that observed in European populations. In Brazilians of African ancestry this value was very high (12% to 15%). This allele was not observed in the only two African populations investigated thus far. By themselves, the two factors of interethnic admixture (with populations of European descent and/or Amerindian populations) and genetic drift cannot explain the high values observed here. Our findings suggest that the CYP1A1*2C allele may possibly be present in Africa, but restricted to some ethnic groups not yet investigated. Environmental factors in South America might also have acted as selective factors increasing the CYP1A1*2C gene frequency. Our data also suggest that the CYP1A1*2C allele might possibly have originated in Africa