The origin of the contribution of uniparental heritage were analyzed in 615 samples of individuals proceeding from 13 towns classified according to historic differences in their emergence and development as African-derived, European-derived, and admixed/urban. Mitochondrial and Y-chromosome haplogroups were identified by PCR-restriction fragment length polymorphism. The results were compared with previous estimates of admixture made with autosomal markers and with historic aspects. The results show a predominantly indigenous genetic contribution through the female, being more prevalent in urban populations; the African contribution, although dispersed, presents a larger concentration in the African-derived towns, whereas the European contribution is limited to populations with this origin, reflecting isolation and the conservation of the distribution pattern of genes of the Colonial era. With regard to admixture through males, it is almost exclusively of European origin, whereas the African contribution is basically concentrated in the African-derived towns, and the Amerindian lineages are almost nonexistent. The genome of paternal heredity, as opposed to the autosomal and the mitochondrial, shows a homogeneous pattern of admixture that is independent of the origin of the population studied, suggesting that European genes have been introduced into the Venezuelan population through male immigrations, whereas the indigenous contribution has been preserved in the Venezuelan genetic pool through the women. These results provide evidence of the heterogeneity in the genetic origin of the Venezuelan population, which should be taken into account in forensic and epidemiologic genetic studies.

In order to study the origin of mutation HBB*S in Sucre and Anzoátegui states and the genetic affinities of these Venezuelan populations with other human groups, the beta-globin gene cluster haplotypes were determined for 28 sickle cell and/or S-beta thalassemia patients and for 37 individuals with normal hematological parameters. Bantu, Benin, Senegal, and atypical haplotypes were identified in 50%, 36%, 2%, and 12% of the HBB*S chromosomes, respectively. Similar results have been published for Venezuelan patients from the central states, but a different trend is shown in a publication based on a group of patients from different regions of the country. For HBB*A, haplotype 2 (+ - - - -), characteristic of non-African groups, was the most common (39%), followed by haplotype 3 (- - - - +) of African origin, and haplotype 6 (- + + - +), also typical of non-Africans. The results reveal a high level of admixture of the Sucre-Anzoátegui population. The importance of specific conditions which have acted differently in the Venezuelan populations, such as founder effect, genetic drift, isolation, and endogamy are discussed. Genetic distances between the Sucre-Anzoátegui sample and several other human populations calculated on the basis of the HBB*S and HBB*A haplotypes revealed similar results, the closest genetic relationships being observed in relation to Bantu-speaking groups. These results confirm the utility of the beta-globin haplotypes for population studies and contribute to knowledge of the Venezuelan gene pool.

These results support the need to understand the distribution of genomic biomarkers related to the metabolism of drugs, for planning national public health strategies.

Background: Numerous single nucleotide polymorphisms (SNPs) located in chromosomal region 9p21 have been associated with cardiovascular disease, most of these studies in European populations. We have no knowledge of studies conducted in admixed populations populations as the Latin Americans. For this reason we decided to study the association of SNPs rs2383206, rs10757274 and rs10757278, together with some non-genetic factors with arterial thrombotic events (AT), in individuals from the north-eastern portion of Venezuela. Methods: Gender, age and non-genetic risk variables were evaluated in 119 patients with AT and 119 control subjects. Genotypes were identified using TaqMan probes. The odds ratio (OR) for genotypes alone and in conjunction with non-genetic variables were estimated. Results: There was a consistent association of rs10757278 with AT, increased in males (OR=2.38). The medium-low socioeconomic status also confers a significant risk for AT in both sexes (OR=4.04). Haplotypes with at least two A alleles, proved to be protective (OR=0.53) in developing arterial thrombosis. Conclusions: There was a consistent association with AT for the rs10757278 polymorphism, increased in males. Sex and socioeconomic status were also significant risk factors in this study reinforcing the importance in studying other variables such as environmental and sex differences together with the genetic structure of each population when analyzing risks for AT diseases. These results serve as a guide when searching for markers of risk for this disease common in Venezuela.