Sandra Mara Bispo Sousa

Diversidade genética da soja entre períodos e entre programas de melhoramento no Brasil

The objective of this work was to detect the effects of plant breeding over the genetic diversity of soybean germplasm grown during the last three decades by comparing six different breeding programs and releasing intervals of soybean cultivars, using microsatellite loci. Regarding the breeding programs, all loci presented significantly different allelic distributions. Some loci presented alleles restricted to unique breeding programs, while others had a same allele being the most frequent in all the six programs. The AMOVA revealed that the major proportion of the variance occurred among cultivars within breeding programs and only 5.3% (p 0.05). The results suggest that the soybean germplasm pool involved in breeding programs in Brazil has maintained a stable genetic diversity during the past 30 years, in addition to a relative heterogeneity of some breeding programs.

TNF Microsatellite Alleles in Brazilian Chagasic Patients

To evaluate the tumor necrosis factor (TNF) a–e microsatellite polymorphism in Chagasic patients, we studied 162 patients stratified according to the major clinical variants (cardiac, digestive, digestive plus cardiac, and indeterminate forms) and 221 healthy controls. TNF microsatellite alleles were typed using genomic DNA amplified with specific primers. Statistical analyses were performed using the GENEPOP and ARLEQUIN softwares and the two-tailed Fisher exact test. The TNFa2, TNFa7, TNFa8, TNFb2, TNFb4, TNFd5, TNFd7, and TNFe2 alleles were overrepresented, whereas the TNFb7 and TNFd3 alleles were underrepresented when clinical variants of Chagas’ disease or the patient group as a whole were compared with controls. Twelve TNF haplotypes were associated with susceptibility to or protection against Chagas’ disease, considered as a whole or stratified into clinical variants. Many of these haplotypes encompassed the above-described susceptibility/protective alleles. These results indicate that the TNF chromosomal region is relevant for Chagas’ disease development.

Afro-derived Brazilian populations: male genetic constitution estimated by Y-chromosomes STRs and AluYAP element polymorphisms.

The genetic constitution of Afro‐derived Brazilian populations is barely studied. To improve that knowledge, we investigated the AluYAP element and five Y‐chromosome STRs (DYS19, DYS390, DYS391, DYS392, and DYS393) to estimate ethnic male contribution in the constitution of four Brazilian quilombos remnants: Mocambo, Rio das Rãs, Kalunga, and Riacho de Sacutiaba. Results indicated significant differences among communities, corroborating historical information about the Brazilian settlement. We concluded that besides African contribution, there was a great European participation in the constitution of these four populations and that observed haplotype variability could be explained by gene flow to quilombos remnants and mutational events in microsatellites (STRs). Am. J. Hum. Biol., 2009.

Heterogeneous Distribution of HbS and HbC Alleles in Afro-derived Brazilian Populations

Abstract Africans brought to Brazil as slaves established communities known as Quilombos. As a consequence of this migration, sickle cell diseases are currently the most frequent hemoglobinopathy in the country. We sampled and analyzed for the presence of HbS and HbC 1182 individuals belonging to 11 remnants of Quilombo communities, distributed over three administrative regions of Brazil. Our results were pooled with literature data, resulting in the analysis of 2601 individuals from 24 populations distributed over the five Brazilian administrative regions. There were differences among weighted averages frequencies for the five Brazilian regions, and there were remarkable heterogeneities among all populations and the ones located in the same region. Additionally, we evaluated the utilization of the test of solubility and its efficiency in the field in three communities, reinforcing the reliability of the test as a first screening of hemoglobinopathy. Frequencies of hemoglobin S allele ranged from 0 to 13% and HbC allele was absent in 18 out of the 24 communities. The distribution of HbS and HbC alleles in remnants of Quilombos are heterogeneous and independent of geographic location probably due to differences in their history of foundation and miscegenation.

Does celiac disease occur in Afro-derived Brazilian populations?

Celiac disease is an autoimmune disorder that occurs in genetically susceptible individuals in whom the ingestion of dietary gluten induces intestinal mucosa inflammation. Previous studies suggest that celiac disease may either be very rare or underdiagnosed in African and/or African‐derived population.

Glomerular filtration rate is altered in children with sickle cell disease: a comparison between Hb SS and Hb SC

Background Renal failure is common among older patients with sickle cell disease; this is preceded by subclinical glomerular hyperfiltration. Data about renal function of adults with sickle cell disease have been reported, but data on children is scarce, especially when comparing heterozygotic and homozygotic patients. Objective The goal of this study was to investigate the glomerular filtration rate of heterozygotic and homozygotic children with sickle cell disease. Methods The glomerular filtration rate of 11 children with sickle cell disease [7 homozygotic (SS) and 4 heterozygotic (SC)] with a mean age of 11 years (standard deviation: ± 5 years) was evaluated using standard laboratory techniques. Results are presented as descriptive analysis. Results Our results suggest that glomerular hyperfiltration is present in children with sickle cell disease; this is more evident in homozygotic than heterozygotic children. Conclusion There is evidence of a need to monitor the renal function of children with sickle cell disease when special attention should be paid to homozygotic patients.

CCR5D32 mutation in three Brazilian populations of predominantly Sub-Saharan African ancestry

Abstract This study reports the frequencies of the CCR5D32mutation of the β-chemokine 5 gene and discusses the possibleeffectsofpastandrecentgeneflowinthreequilomboremnants(BrazilianscommunitieswithanthropologicalAfricanancestry whose ancestors were escaped slaves): Rio das Ras, Mocambo, and Sao Goncalo in the northeasternregionofBrazil.TheCCR5D32allelefrequencyoftheMocambopopulationwassignificantlyhigher(5.6%)thanthatfound in the Rio das Ras (1%) and Sao Goncalo (0.9%) populations. These differences may reflect differentproportions of parental populations in the founders individuals, a founder-effect and/or different histories ofinter-ethnic contact. The frequency of the CCR5D32allele in the Mocambo sample is similar to that found in thoseurbanBrazilianpopulationswhichhavealargeamountofEuropeangeneticinput,indicatingaEuropeancontributionto the gene pool of this population and suggesting that, perhaps since its foundation, Mocambo has had a high levelof admixture or experienced a founder-effect.

Y-Linked microsatellites in Amazonian Amerindians applied to ancestry estimates in Brazilian Afro-derived populations

Proper ancestral populations are required to determine accurate ancestry estimates for Afro‐derived Brazilian populations. Herein, we have genotyped Y‐STRs in Amazonian Amerindians to determine the ancestral contribution in quilombo remnant communities.