Investigation of forensic activity values of 12 x-STR locus

Aim: Short Tandem Repeats(STRs) on the X chromosome can be used as supportive for STRs in autosomal chromosomes, forensic identification and lineage research. Since allel frequencies of X STR loci vary among populations, for statistical analysis for forensic identification and pedigree analysis, population-specific database should be established. Material and Method: This study was carried out to determine the allele / haplotype frequency distribution and forensic efficiency values of the 12 X-STR loci (DXS7132, DXS7423, DXS8378, DXS10074, DXS10134, DXS10105, DXS10103, DXS10134, DXS10135, DXS10146, DXS10148 and HPRTB). In this study, biological samples were used taken from 137 subjects (84 females, 53 males) who were randomly selected from the patients who applied for DNA analysis in Çukurova University Faculty of Medicine Department of Forensic Medicine. In the samples, 12 X-STR loci were amplified after DNA isolation with instagene matrix and PCR products were genotyped after capillary electrophoresis. Results: A total of 126 alleles were identified in the 12 X-STR loci studied. It was observed that the locus with the most alleles was DXS10148 with 31 alleles and with the least alleles was DXS8378 with 5 alleles. In the analysis performed with 84 diploid samples, there was no deviation in Hardy Weinberg Balance after Bonferroni correction test (p = 0.05 / 12). It was observed that the locus which had the highest discriminating capacity within the studied loci was DXS10135 (PDFemale = 0.995396, PDMale = 0.951127) and the locus with the lowest discriminating power was DXS8378 (PDFemale = 0.826910; PDMale = 0.669670). For 53 haploid samples, when haplotypes of the linked groups were examined, in the linking group 1 (Linkage Group 1-LG1), LG2, LG3 and LG4, 50, 46, 39 and 46 different haplotypes were identified, respectively, and for each linked group, the least Power of Discrimination-PD value was calculated as 0.94. Cumulatif PD value of 4 LG groups was found over 0.999999. Conclusion: The statistical data obtained from this study revealed that the Argus X-12 STR panel developed for the 12 X-STR locus was highly polymorphic and informative in the Turkish population; especially in paternity cases where the father's analysis cannot be done, and a strong complementary tool in revealing complex kinship relations.