Genetic characterization of the population of São Luís, MA, Brazil

Five loci (vWA1, F13A1, D12S67, Apo-B and D1S80) were investigated by polyacrylamide gel electrophoresis followed by silver staining in a sample of 177 individuals from the population of São Luís, State of Maranhão, Brazil. A total of 70 different alleles were identified. A statistically significant deviation from the Hardy-Weinberg equilibrium was observed in a single locus (F13A1, p = 0.0075). The average heterozygosity (H) was estimated at 77.7%, the mean number of alleles per locus as 14. The PD (capacity of genotype differentiation at each locus) ranged from 88.9% (vWA1) to 96.7% (F13A1). The combined PE (power of exclusion) of these five loci was 99.8%. In terms of racial admixture (42% European, 39% Indian, and 19% African Black ancestry), São Luís presented an estimate similar to Belém, another trihybrid Amazonian population.

Haplotype diversity of 17 Y-str loci in an admixed population from the Brazilian Amazon

The allelic and haplotype frequencies of 17 Y-STR loci most commonly used in forensic testing were estimated in a sample of 138 unrelated healthy males from Macapá, in the northern Amazon region of Brazil. The average gene diversity was 0.6554 ± 0.3315. 134 haplotypes of the 17 loci were observed, 130 of them unique and four present in two individuals each. The haplotype diversity index was 0.9996 + 0.0009, with the most frequent haplogroups being R1b (52.2%), E1b1b (11.6%), J2 (10.1%) and Q (7.2%). Most haplogroups of this population belonged to European male lineages (89.2%), followed by Amerindian (7.2%) and African (3.6%) lineages.

Allelic frequencies and statistical data obtained from 12 codis STR loci in an admixed population of the Brazilian Amazon

The allelic frequencies of 12 short tandem repeat loci were obtained from a sample of 307 unrelated individuals living in Macapá, a city in the northern Amazon region, Brazil. These loci are the most commonly used in forensics and paternity testing. Based on the allele frequency obtained for the population of Macapá, we estimated an interethnic admixture for the three parental groups (European, Native American and African) of, respectively, 46%, 35% and 19%. Comparing these allele frequencies with those of other Brazilian populations and of the Iberian Peninsula population, no significant distances were observed. The interpopulation genetic distances (F_ST coefficients) to the present database ranged from F_ST = 0.0016 between Macapá and Belém to F_ST = 0.0036 between Macapá and the Iberian Peninsula.