Evaluation and Mutational Analysis of 13 Rapidly Mutating Y-STRs in Gilgit Population of Pakistan with a Forensic Casework Study

Abstract

Y-chromosomal Short Tandem Repeats (STR) have been widely used in forensic investigations, identification of males for criminal justice purpose and population genetics. Commercially available Y-STRs kits allow the identification of male pedigrees and has a limited application in forensic genetics because of its limitation in differentiating closely related male individuals. Recent research on the Rapidly Mutating Y-STRs (RM Y-STRs) have revealed that these loci deliver significantly higher discrimination capacity and haplotype diversity in worldwide populations when compared with the conventional Y-STRs. Although several RM Y-STRs have found their way in most updated commercial kits, there are still some loci that are not yet used in such kits. The aim of this study was to develop RM Y-STR haplotypes frequency database for the Pakistani population, and to appraise the resolution power of these loci. A total of 212 unrelated males from the Pakistani population were typed with 13 RM Y-STRs which comprise DYF399S1, DYF387S1, DYS570, DYS576, DYS518, DYS526a + b, DYS626, DYS627, DYF403S1a + b, DYF404S1, DYS449, DYS547 and DYS612. 211 unique haplotypes were identified, out of which 1 haplotype was shared between two individuals, accounting for 0.9952 discrimination capacity (DC). Haplotype diversity was found to be 0.999925. Gene diversity (GD) values of all the loci were higher than 0.5, where the highest GD values were observed at DYF399S1, DYF403S1a and DYF404S1; with values of 0.99419, 0.98252 and 0.93061 respectively. Results of our study revealed that these 13 RM Y-STRs produced significantly stronger discriminatory power in Pakistani populations. Because these are totally transferred to the future generations until mutations occur, Y chromosome genetic markers are commonly utilized in forensics for the classification of male lineages for criminal justice purposes. The mutation rate of Rapidly Mutating Y-STRs (RM Y-STRs) markers is high. That is not observed in other Y-STRs markers, and they appear to be effective in distinguishing paternally related men. This study aimed to estimate the population and mutational parameters of 13 RM Y-STRs in 13 unrelated males born in Gilgit, Pakistan. Repeat there was no population substructure and strong discriminating capacity in the counts. In this population, there DRSML QAU viii were higher mutation rates with the unusual structure of repeats. More research is needed to better characterize these loci in diverse Pakistani groups. In several fields of human genetics, the Y-STR polymorphism is significant in societies with high levels of inbreeding, Y-chromosome STRs frequently utilized in forensic medicine exhibit little haplotype variation and resemble male cousins of the same ancestry. Y-STRs that quickly modify (RM Y-STRs) have garnered a large amount of attention in the previous ten years. These 13 RM Y-STRs exhibit repeatability in connection to paternal changes in interspecific populations due to their high mutation rate (>10-2 ) and significantly higher discrimination and haplotype diversity compared to the commonly used Y-STRs. 130 father-son pairs from the Gilgit Baltistan region of Pakistan were explored in this study for the first time. While DYF399 and DYF403 frequently displayed mutations, DYS526a/b did not. Additionally, using father-son pair data from the current and earlier investigations, we need updated RM Y-STR mutation rates. Mutation rates for DYS626a extended since 1.90 X 10-3 (7.0 X 10-4 to 4.0 X 10-3 ) to 7.45 X 10-2 (6.58 X 10-2 to 8.39 X 10-2 ) and those aimed at DYF399S1 from 6.58 X 10-2 to 8.39 X 10-2 , respectively, when compared to recently published data. These estimates provide the best precise mutation rates used aimed at the 13 RM Y-STR markers, with 2949 (DYS570) to 3327 (DYF387S1) meioses currently separating each marker. The normal mutation rate for the entire 13 RM Y-STR markers remained 1.84 X 10-2 , established upon a sum of 878 mutations as of 47731 meiosis events. (1.72 X 10-2 - 1.96 X 10-2 ). (Table 5.1)