Population data for six X-chromosome STR loci in a Rio de Janeiro (Brazil) sample: Usefulness in forensic casework

This study presents data for the X-chromosome STR loci DXS7133, DXS7424, DXS8378, DXS6807, DXS7423 and DXS8377. In order to establish a database, unrelated individuals (males and females) from Rio de Janeiro were typed for the above loci. No significant differences were observed between allele frequencies in male and female samples (non-differentiation exact P values ≥ 0.156). Hardy-Weinberg equilibrium was tested in the female sample and no significant deviations were found. All six markers have shown to be highly polymorphic in our sample with gene diversities varying between 0.6797 for DXS7133, and 0.9260 for DXS8377. Pairwise linkage disequilibrium analysis did not allow discharging a possible association between DXS7133 and DXS7424 alleles in Rio de Janeiro population. Parameters of forensic interest, like PD_M, PD_F, Het_obs, Het_exp, were calculated for each locus. The high discrimination power estimated in both males and females, as well as mean exclusion chance in father/daughter duos and in father/mother/daughter trios, demonstrates the usefulness of these six markers in forensic investigation.     

Y-chromosomal STR haplotypes in a Gypsy population from Portugal

We analyzed 17 Y-chromosomal STR loci in a population sample of 126 unrelated Portuguese Gypsies. Fifty three different haplotypes were found, three represented with considerable high frequencies (≥8.7%). The percentage of unique haplotypes (71.2%) was rather low as well as haplotype diversity (94.37%). In the comparison with available Portuguese population data and with those from other Gypsy and general population samples from Bulgaria, Lithuania and Spain, our sample showed significant differences in comparison with the general population data from Portugal, Spain and Bulgaria. Significant differences were observed with Bulgarian Gypsies, but not with the Spanish or Lithuanian groups. The Gypsy populations from Portugal, Spain and Bulgaria were found to be more closely related to each other than with the general population from their own countries.     

Study-release policies of American correctional agencies: A survey

The results of a survey conducted to determine the extent and effectiveness of present correctional study-release programs and policies are presented, and direction is offered for the expansion of such programs based on current practices.     

Mismatch distribution analysis of Y-STR haplotypes as a tool for the evaluation of identity-by-state proportions and significance of matches--the European picture

We suggest the use of the mismatch distribution methodology as an easy way to estimate the distance between all pairs of haplotypes present in a sample. This approach allows the evaluation of the proportion of pairs of Y-STR haplotypes that are prone to become identical by state (IBS), in one generation, by recurrent mutation, a statistic of major importance in the forensic field. The mismatch approach presents some advantages alternatively to the empirical one, since it is not necessary to have simultaneous information on STRs and SNPs, and it allows the evaluation of IBS also within-haplogroups. The estimation of IBS at an European scale showed that there is a high population substructuring for this parameter, increasing from southern-central European countries towards west and north, in accordance to what was found for Y-biallelic markers. This result seems to imply a more careful use of large databases for matching evaluation, even in the absence of population structure for general Y-STR diversity. Furthermore, mismatch distribution can be used to measure the distance between a particular haplotype and all the haplotypes in a sample. When applied to the most frequent haplotypes in Europe it revealed that the opportunity for IBS is not directly related to the frequency of a haplotype, but highly dependent on the proportion of neighbouring haplotypes--so, that reporting on the haplotype frequency for evaluating the significance of a match can be misleading.     

STR allelic frequencies for an African population sample (Equatorial Guinea) using AmpFlSTR Identifiler and Powerplex 16 kits

We present allele frequencies and forensic parameters for 17 STRs included in the AmpFlSTR Identifiler (CSF1PO, D2S1338, D3S1358, D5S818, D7S820, D8S1179, D13S317, D16S539, D18S51, D19S433, D21S11, FGA, TH01, TPO and VWA) and Powerplex 16 System (CSF1PO, D3S1358, D5S818, D7S820, D8S1179, D13S317, D16S539, D18S51, D21S11, FGA, Penta D, Penta E, TH01, TPO and VWA) in a sample of 134 unrelated individuals from Equatorial Guinea located in Western Africa, between Cameroon and Gabon. Hardy-Weinberg equilibrium was tested for each locus and the sample was compared with five African databases: Promega's and AB Applied Biosystems African-Americans and samples from Mozambique, from Cabinda (Angola) and Guinea-Bissau.     

Population data on 15 autosomal STRs in a sample from East Timor

Allele frequencies for the fifteen STRs included in the AmpF/STR Identifiler (CSF1PO, D2S1338, D3S1358, D5S818, D7S820, D8S1179, D13S317, D16S539, D18S51, D19S433, D21S11, FGA, TH01, TPO and VWA) were estimated from a sample of 186 unrelated individuals from East Timor. No deviations from Hardy-Weinberg equilibrium were observed (only after applying the Bonferroni correction in the cases of D2S1338, TPO and D5S818). Genetic parameters of forensic interest were calculated and comparison with geographically nearby populations was performed.