Estimates of African, European, and Amerindian contribu- tions to the gene pool of 11 predominantly African-derived South American populations were obtained using five autosomal and one Y chromosome hy- pervariable loci, as well as mitochondrial DNA (sequences of the first hyper- variable segment of the control region, plus two restriction sites and the presence or absence of the CoII/tRNA Lys intergenic 9-bp deletion). The three latter characteristics are reported here for the first time for 42 individuals living in three Brazilian populations. Thirty-eight sequences were identified in these persons; 17 (45%) could be classified as being of African, 4 (11%) of Amerindian, and 2 (5%) of European origin. Evidence for asymmetrical mat- ings in relation to sex and ethnic group was obtained for nine of the 11 populations. The most consistent finding was the introduction of European genes through males, but the results differ in the several communities, in- dicating the importance of local factors in such interactions. Am. J. Hum. Biol. 11:551-563, 1999. © 1999 Wiley-Liss, Inc.

African-derived South American populations: A history of symmetrical and asymmetrical matings according to sex revealed by bi- and uni-parental genetic markers.

Plasmodium vivax radical cure requires the use of primaquine (PQ), a drug that induces haemolysis in glucose-6-phosphate dehydrogenase deficient (G6PDd) individuals, which further hampers malaria control efforts. The aim of this work was to study the G6PDd prevalence and variants in Latin America (LA) and the Caribbean region. A systematic search of the published literature was undertaken in August 2013. Bibliographies of manuscripts were also searched and additional references were identified. Low prevalence rates of G6PDd were documented in Argentina, Bolivia, Mexico, Peru and Uruguay, but studies from Curacao, Ecuador, Jamaica, Saint Lucia, Suriname and Trinidad, as well as some surveys carried out in areas of Brazil, Colombia and Cuba, have shown a high prevalence (> 10%) of G6PDd. The G6PD A-202A mutation was the variant most broadly distributed across LA and was identified in 81.1% of the deficient individuals surveyed. G6PDd is a frequent phenomenon in LA, although certain Amerindian populations may not be affected, suggesting that PQ could be safely used in these specific populations. Population-wide use of PQ as part of malaria elimination strategies in LA cannot be supported unless a rapid, accurate and field-deployable G6PDd diagnostic test is made available.

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G6PD deficiency in Latin America: systematic review on prevalence and variants.

A total of 582 individuals (1,164 chromosomes) from two African, eight African-derived South American, five South American Amerindian, and three Brazilian urban populations were studied at four variable number of tandem repeat (VNTR) and two short tandem repeat (STR) hypervariable loci. These two sets of loci did not show distinct allele profiles, which might be expected if different processes promoted their molecular differentiation. The two African groups showed little difference between them, and their intrapopulational variation was similar to those obtained in the African-derived South American communities. The latter showed different degrees of interpopulation variability, despite the fact that they presented almost identical average degrees of non-African admixture. The FST single locus estimates differed in the five sets of populations, probably due to genetic drift, indicating the need to consider population structure in the evaluation of their total variability. A high interpopulational diversity was found among Amerindian populations in relation to Brazilian African-derived isolated communities. This is probably a consequence of the differences in the patterns of gene flow and genetic drift that each of these semi-isolated groups experienced. Am J Phys Anthropol 109:425–437, 1999. © 1999 Wiley-Liss, Inc.

Genetic diversity of two African and sixteen South American populations determined on the basis of six hypervariable loci.

A total of 2,708 individuals from the European-derived population of Rio Grande do Sul, divided into seven mesoregions, and of 226 individuals of similar origin from Santa Catarina were studied. Seventeen protein genetic systems, as well as grandparents' nationalities, individuals' surnames, and interethnic admixture were investigated. The alleles which presented the highest and lowest differences were GLO1*2 (16%) and PGD*A (2%), respectively, but in general no significant genetic differences were found among mesoregions. The values observed were generally those expected for individuals of European descent, with the largest difference being a lower prevalence (34-39%) of P*1. Significant heterogeneity among mesoregions was observed for the other variables considered, and was consistent with historical records. The Amerindian contribution to the gene pool of European-derived subjects in Rio Grande do Sul was estimated to be as high as 11%. Based on the four data sets, the most general finding was a tendency for a northeast-southwest separation of the populations studied. Seven significant phenotype associations between systems were observed at the 5% level (three at the 0.1% level). Of the latter, the two most interesting (since they were also observed in other studies) were MNSs/Duffy and Rh/ACP.

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Genetics, surnames, grandparents' nationalities, and ethnic admixture in southern Brazil - do the patterns of variation coincide?

Sequence data from the first hypervariable segment of the mitochondrial DNA control region of 124 subjects belonging to three African-Brazilian and three Brazilian Indian populations were compared with information related to 12 protein genetic loci from 601 persons living in the same localities. There is high diversity among the mtDNA sites, and the most variable in one ethnic group are not the most variable in the other. No differences in gene diversity between populations within ethnic groups were observed, but the Indians showed a reduced variability. Much more interpopulation variation was observed in the mtDNA data than in the protein set. The relationships obtained for the six populations, however, are the same regardless whether mtDNA or protein loci are considered. African-Brazilians from Porto Alegre and Salvador, situated 3,000 km apart, are more similar to each other than both are to Paredao, despite the geographical proximity between Porto Alegre and Paredao, which are just 50 km apart. The tree topology in relation to the three Indians groups, on the other hand, is that expected when languages, culture, and geography are considered.

Genetic variability in two Brazilian ethnic groups: a comparison of mitochondrial and protein data.

A total of 218 individuals living in the Brazilian cities of Porto Alegre (in the South) and Salvador (in the Northeast) were variously studied in relation to nine erythrocyte and four plasma protein systems. The results were compared with previous studies in some of these systems, and estimates of interethnic admixture obtained in subsamples according to morphological appearance. As a whole, Afro-Brazilians from Salvador show 42% of non-African genes, the corresponding figure for Porto Alegre being 59%. The Amerindian contribution to these individuals was estimated as null or negligible. Average heterozygosities are similar to those obtained for African groups, but the gene differentiation coefficient (GST') is small. The phylogenetic tree indicates a closer relationship of Salvador with the African subcluster, as would be expected by the admixture and istorical data. Analyses such as this one are important for the unraveling of the complex networks responsible for the present variability of human populations, and for the dispelling of racist concepts.

L. B. Moura

Papers

Genetic structure of two urban afro-brazilian populations