André Zoratto Gastaldo

Mutation rate estimates for 13 STR loci in a large population from Rio Grande do Sul, Southern Brazil

Short tandem repeat (STR) polymorphisms have been extensively used in forensic genetics analysis. Knowledge about the locus-specific mutation rates of STRs improves forensic probability calculations and interpretations of diversity data. To incorporate single-locus diversity information into autosomal STR mutation rate estimations, 13 STR loci were studied during 2007–2009 in 10,959 paternity investigation cases from Rio Grande do Sul, the southernmost state of Brazil, covering an overall number of 284,934 allelic transfers. A total of 355 mutations were identified; 348 repeats were gains or losses of one step, three were gains or losses of two steps, and four were gains or losses of not stepwise mutation. The mutation rates ranged from 4.6 × 10−5 to 2.3 × 10−3, and the overall mutation rate estimate was 1.2 × 10−3. The average of the paternal mutation rate (1.8 × 10−3) was five times higher than the maternal rate (0.36 × 10−3). The observed mutational features for STRs have important consequences for forensic applications, including the definition of criteria for exclusion in paternity testing and the interpretation of DNA profiles in identification analysis.

15 STR loci frequencies with mutation rates in the population from Rio Grande do Sul, Southern Brazil

Allele frequencies for 15 short tandem repeats (STR) loci were obtained from a sample of 2038 individuals undergoing paternity testing. The population is from Rio Grande do Sul, Brazil. The loci are the most commonly used in forensic and paternity testing, being analysed by the AmpFlSTR Identifiler (Applied Biosystems) commercial kit. The most polymorphic locus was D2S1338. Mutation rates were ascertained from this population sample. All the loci analysed reached the Hardy-Weinberg equilibrium. The results of genetic distance are consistent with the European-derived origins of Rio Grande do Sul population.

Population genetic data for 11 STR loci, including SE33, in Southern Brazil

Allele frequencies for 11 STR autosomal loci (D3S1358, vWA, D16S539, D2S1338, D8S1179, SE33, D19S433, TH01, FGA, D21S11, D18S51) were analysed in unrelated individuals undergoing paternity testing in Rio Grande do Sul State, Southern Brazil. The most polimorphic locus was SE33. The distributions of the genotypes in the evaluated loci are in Hardy-Weinberg equilibrium after Bonferronis correction.

Investigation of paternity with alleged father deceased or missing: Analysis of success at the end of the report

In this work we present a retrospective study of 858 cases of paternity investigation performed in Rio Grande do Sul, Southern Brazil, from 2007 to 2012, where the alleged father was deceased or missing. These cases represent 3.3% (858/26187) of paternity tests performed in that period. Considering the analysis of 17 DNA short tandem repeat loci, we present here the proportion of cases with conclusive results according to the number of relatives of the unavailable alleged father investigated and their kinship. The results show 81.0% (695/858) of cases with conclusive results and their characteristics.