Ahmad Ferdous

Haplotype diversity of 17 Y-chromosomal STR loci in the Bangladeshi population

Haplotype and allele frequencies of 17 Y-chromosomal STR loci were determined in 216 unrelated Bangladeshi males. AmpFlSTR Y-filer PCR Amplification kit (Applied Biosystems) was used to type the following Y-STR markers: DYS19, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS385a/b, DYS438, DYS439, DYS437, DYS448, DYS458, DYS456, DYS635, and Y-GATA-H4. A total of 211 haplotypes for the 17 Y-STR markers were detected and, of these, 206 haplotypes were unique. The haplotype diversity was 0.9998, indicating a high potential for differentiating between male individuals in this population. Comparison analysis via Analysis of Molecular Variance (AMOVA) and construction of Neighbor Joining Tree revealed a close association of Bangladeshi population with Indian Gaddi and Southern Indian populations.

Forensic evaluation of STR data for the PowerPlex™ 16 System loci in a Bangladeshi population

Allele frequencies of 15 autosomal STR loci included in PowerPlex 16 System were determined from a sample of 148 unrelated Bangladeshi individuals. Forensic efficiency parameters such as, the power of discrimination (PD), observed and expected heterozygosity (H), polymorphism information content (PIC), probability of match (PM), power of exclusion (PE), and typical paternity index were calculated for the loci. These parameters indicated the usefulness of the loci in paternity testing and personal identification in the Bangladeshi population.

Allele Frequencies of 10 Autosomal STR Loci from Chakma and Tripura Tribal Populations in Bangladesh

Allele frequencies of ten autosomal STR loci, D3S1358, vWA, D16S539, D2S1338, D8S1179, D21S11, D18S51, D19S433, TH01, and FGA were investigated in Chakma and Tripura tribal populations of Bangladesh. In both the populations, all loci were in Hardy-Weinberg equilibrium except for FGA locus in Chakma and D21S11 in Tripura. All the loci were highly polymorphic in Chakma population with an observed heterozygosity (Ho) of >0.7 and moderately polymorphic in Tripura population (Ho > 0.6). However, both the population showed least polymorphism at TH01 locus (Ho < 0.6). A comparison between Chakma and Tripura population data revealed statistically significant differences in allele frequency distribution for most of the loci. A similar comparison with the mainstream Bengali population using previously published data from this lab also showed significant difference in allele frequency with these two tribal populations.

Forensic evaluation of 11 non-standard STR loci in Bangladeshi population.

Allele frequencies and forensic efficiency parameters of 11 non-standard autosomal STR loci, D21S1437, D22S683, D8S1110, D10S2325, D12S1090, D17S1294, D3S1744, D14S608, D20S470, D18S536 and D13S765 were evaluated in a sample of 102 unrelated Bangladeshi individuals. No significant deviation from Hardy-Weinberg equilibrium was observed in any of the loci studied. Statistical parameters of forensic importance, the power of discrimination (PD), observed and expected heterozygosity (H), polymorphism information content (PIC), matching probability (MP), power of exclusion (PE) and typical paternity index (TPI) were calculated for the loci. The most informative locus among the 11 STR loci was D10S2325 (PD=0.958), while the least informative was D17S129 (PD=0.876). The combined PD (1-PM) and MP was calculated to be 0.9999999999997 and 2.23×10(-23), respectively. These parameters indicated the usefulness of the loci in forensic personal identification and parentage testing among Bangladeshi population.

False paternity with one or two mismatches using commercial STR kits

This study presents a case of false paternity where one or two mismatches were found by using three commercial STR kits. The analysis with the Identifiler kit yielded two mismatches at the loci D2S1338 and vWA. These data did not, however, enable us to exclude the alleged father, as the total number of excluding loci was less than three. Further STR loci were therefore employed to resolve the case. The PowerPlex 16 system yielded only one mismatch at the vWA locus previously found with the Identifiler kit. GenePhile G-Plex, on the other hand yielded two inconsistencies at D3S1744 and D18S536 (out of 15 loci in total). Since the disputed child was a female and we were not able to exclude the possible involvement of a close male relative, we choose to use Genephile X-Plex kit to finally resolve the case. Out of 13 loci tested, we found a complete match of the childs profile with the mother and eight mismatches with the alleged father, clearly indicating that the alleged father is not the biological father. This case emphasizes the usefulness of either Y-chromosome or X-chromosome DNA data for interpreting borderline paternity cases.