and Ândrea Kely Campos Ribeiro-dos-Santos2 1Universidade Federal do Maranhão, Laboratório de Genética e Biologia Molecular,

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