Genetic Polymorphism and Forensic Parameters of 36 Autosomal InDel Markers in the Azerbaijani Population

Abstract— InDel (insertion/deletion) loci have started to be used alone or as a complementary marker to other markers in forensic sciences due to their advantages such as high heterozygosity rates and discrimination power, low mutation rates, small amplicon sizes and low cost of analysis. This study aims to analyze the population structure and gene frequencies of the autosomal 36-InDelplex panel, developed by Filoğlu et al., within the Azerbaijani population. Additionally, the study evaluates the forensic statistical parameters of this panel to assess its effectiveness for forensic identification and kinship determination in this population. Buccal swab samples were collected from 182 unrelated healthy volunteers (92 females, 90 males) for this study. DNA analyses were performed by PCR and analysed on an Applied Biosystems™ 3500 Genetic Analyzer with genotypes determined using GeneMapper v.5.0 software. Allele frequencies, genetic distances between populations (F_ST), and Hardy–Weinberg equilibrium were calculated using Arlequin v.3.5.1.2. Phylogenetic trees were constructed based on F_ST values using Mega X v.10.0.5 software. Forensic statistical parameters for each locus were determined using the PowerStats (Promega) Microsoft® Excel file. No deviation from the expected Hardy–Weinberg equilibrium was observed in the studied population. The average heterozygosity across all loci was 0.4807, and the discrimination power was 99.999999999999375124%. Our findings suggest that this panel has potential to provide sufficient discrimination and exclusion power for forensic identification. Comparative analysis of the 36-InDelplex with data from Azerbaijan and various global populations (Africa, America, South Asia, Europe, East Asia, Turkey) revealed that the Azerbaijani population is genetically closer to the populations of Europe and Turkey. The results demonstrate that the 36-plex InDel panel developed for forensic use is highly effective in the Azerbaijani population. The high heterozygosity rates and discrimination power suggest that this panel can be used independently or alongside other genetic markers for identification and kinship determination. Additionally, it is noteworthy that the genetic structure of the Azerbaijani population shows a closer affinity to European and Turkish populations.