Genomic ancestry of rural African-derived populations from Southeastern Brazil.

OBJECTIVES: xMany Africans were brought to Brazil as slaves. The runaway or abandoned slaves founded isolated communities named quilombos. There are many quilombo remnants in Vale do Ribeira region in the southern part of São Paulo State. The aim of our study was to contribute to understanding the origins of these populations, through admixture studies. METHODS: We genotyped 307 unrelated DNA samples obtained from ten quilombo populations from Vale do Ribeira region, using a panel of 48 INDEL polymorphisms. We estimated genetic differentiation between populations (F(ST) ) and genomic ancestry from these populations. Our data were compared to a similar study performed in quilombo remnants from the Brazilian Amazon region. RESULTS: Population admixture estimates showed high degree of miscegenation in the quilombo remnants from Vale do Ribeira (average admixture estimates at 39.7% of African, 39.0% of European and 21.3% of Amerindian contribution). The proportions of ancestral genes varied greatly among individuals, ranging from 7.3 to 69.5%, 12.9 to 68.3%, and 7.3 to 58.5% (African, European, and Amerindian, respectively). Genetic differentiation between these populations was low (all F(ST) values <5%), indicating gene flow between them. Both groups of quilombos, from Vale do Ribeira and Amazon, presented similar patterns of admixture. CONCLUSIONS: INDEL markers were useful to evidence the triple interbreeding among African, European, and Amerindian in the formation of quilombo populations. The low F(ST) values suggested gene flow among quilombos from Vale do Ribeira. Our data highlight the important role of Amerindians in the formation of quilombo populations.

Importância da pesquisa do traço e da anemia falciforme nos remanescentes de Quilombos do Vale do Ribeira - SP

Apresentamos os resultados da triagem molecular de mutações relacionadas à anemia falciforme, hemoglobina S(HBB*S) e hemoglobina C (HBB*C), em 1109 indivíduos de doze populações de remanescentes de quilombos localizadas no Vale do Ribeira, SP, nas imediações dos municípios de Eldorado e Iporanga. Os bairros remanescentes de quilombo estudados foram Abobral Margem Esquerda, Abobral Margem Direita, Galvão, São Pedro, Pedro Cubas, Pilões, Maria Rosa, André Lopes, Nhunguara, Sapatu, Ivaporunduva e Poça. A metodologia empregada foi análise do gene da beta globina amplificado pela reação em cadeia da polimerase (PCR), seguida da digestão com as enzimas de restrição Dde I e Bse RI, que permitem a detecção molecular dos alelos mutados. Identificamos três indivíduos homozigotos (HBB*S/*S, um total de 90 indivíduos com a HBB*S em heterozigose (HBB*S/A), e 3 indivíduos com a hemoglobina C em heterozigose (HBB*C/A). A frequência média de portadores dos alelos mutados em heterozigose foi de 8,5%. Nossos resultados indicaram elevadas frequências do traço falcêmico em várias das populações de remanescentes de quilombos investigadas. Esses dados indicam que essas populações merecem especial atenção em relação à continuidade de programas de triagem dessas hemoglobinopatias. Além disso, o desenvolvimento de programas de esclarecimento e aconselhamento genético voltados à questão da anemia falciforme em remanescentes de quilombo é desejável

Frequency and origins of hemoglobin S mutation in African-derived Brazilian populations.

Africans arrived in Brazil as slaves in great numbers, mainly after 1550. Before the abolition of slavery in Brazil in 1888, many communities, called quilombos, were formed by runaway or abandoned African slaves. These communities are presently referred to as remnants of quilombos, and many are still partially genetically isolated. These remnants can be regarded as relicts of the original African genetic contribution to the Brazilian population. In this study we assessed frequencies and probable geographic origins of hemoglobin S (HBB*S) mutations in remnants of quilombo populations in the Ribeira River valley, São Paulo, Brazil, to reconstruct the history of African-derived populations in the region. We screened for HBB*S mutations in 11 quilombo populations (1,058 samples) and found HBB*S carrier frequencies that ranged from 0% to 14%. We analyzed beta-globin gene cluster haplotypes linked to the HBB*S mutation in 86 chromosomes and found the four known African haplotypes: 70 (81.4%) Bantu (Central Africa Republic), 7 (8.1%) Benin, 7 (8.1%) Senegal, and 2 (2.3%) Cameroon haplotypes. One sickle cell homozygote was Bantu/Bantu and two homozygotes had Bantu/Benin combinations. The high frequency of the sickle cell trait and the diversity of HBB*S linked haplotypes indicate that Brazilian remnants of quilombos are interesting repositories of genetic diversity present in the ancestral African populations.

Polymorphic Alu insertions in six Brazilian African-derived populations.

At least 25 African-derived populations (quilombo remnants) are believed to exist in the Ribeira River Valley, located in the southern part of São Paulo State, Brazil. We studied four Alu polymorphic loci (APO, ACE, TPA25, and FXIIIB) in individuals belonging to six quilombo remnants in addition to individuals sampled from the city of São Paulo. The allelic frequencies observed in the quilombo remnants were similar to those previously observed in African-derived populations from Central and North America. Genetic variability indexes (Fst and Gst values) in our quilombos were higher than the reported values for the majority of other populations analyzed for the same kind of markers, but lower than the variability usually observed in Amerindian groups. The observed high degree of genetic differentiation may be due to genetic drift, especially the founder effect. Our results suggest that these populations behave genetically as semi-isolates. The degree of genetic variability within populations was larger than among them, a finding described in other studies. In the neighbor-joining tree, some of the Brazilian quilombos clustered with the African and African-derived populations (São Pedro and Galvão), others with the Europeans (Pilões, Maria Rosa, and Abobral). Pedro Cubas was placed in an isolated branch. Principal component analysis was also performed and confirmed the trends observed in the neighbor-joining tree. Overall, the quilombos showed a higher degree of gene flow than average when compared to other worldwide populations, but similar to other African-derived populations.

Prevalência da desnutrição em crianças e adolescentes em comunidade de remanescentes de quilombos no sudeste do Estado de São Paulo, Brasil / Malnutrition prevalence in children and adolescents of quilombo remnants in the Southeastem São Paulo State

Estudo de corte transversal para avaliar a prevalência de desnutrição e anemia no universo de menores de 20 anos de comunidades de quilombolas do Sudeste do Estado de São Paulo. Dos 886 menores obteve-se de forma padronizada dados clínicos, antropometricos e dosagem de hemoglobina, após consentimento. Os escores Z evidenciaram baixa prevalência de desnutrição, menor para baixo peso do que para baixa estatura, tendendo a aumentar com a idade. A prevalência de anemia foi elevada, 44,2 por cento, sendo maior nos menores de 4 anos. A análise de regressão logística múltipla identificou como determinantes: renda, numero de pessoas na casa, ausência de esgoto, imunização, idade e sexo do menor.../Cross-sectional study to evaluate prevalence of malnutrition and anemia in the universe of under of 20 years of age of communities of quilombolas in the southeastern of the State of São Paulo. Of the 886 minors it was gotten in a standardized way given clinical, anthropometric data and hemoglobin level, after assent. The Z-score had evidenced low prevalence of malnutrition, less for low weight than for low height, tending to increase with the age. The prevalence of anemia was high, 44.2 per cent, being higher in the under 4. The multiple logistic regression identified as risk factors: income, number of people in the house, absence of sewer, immunization...

Liga de pediatria comunitaria: o futuro medico trabalhando em equipe para promover a saude de criancas carentes / Community pediatric league: the future physician working in a team to promote health in destitute children

A seccao de Assistencia Comunitaria do Instituto da Crianca do Hospital das Clinicas da FMUSP, desde 1996, desenvolve...