Analysis of allele frequencies of the selected 15 autosomal STR markers in Tikrit population – Iraq with comparison to Middle Eastern, African, and Europeans

Abstract

Short tandem repeats (STRs) have been recommended as the highest polymorphic loci among the humana DNA regions. Therefore, STRs are agreeable to many genetic fields like forensic, population genetics and anthropological studies. The main aim of this research is to evaluate the autosomal STRs in Tikrit city-Iraq, to expand the human genetics database and forensic genetics analysis. The DNA database was obtained from 306 unrelated volunteers from native Tikrit population-Iraq, using 15 autosomal STR loci. The current study determined the allele frequencies in the Tikrit population and then compared them with other national Iraqi populations as well as with populations in the Middle East, Africa, and Europe. The highest level of heterozygosity was observed in D8S1179 and TH01 loci (0.797), while the less level was shown by CSF1PO (0.48). The departure from HWE Equilibrium was recorded in only 3 STR loci from a total of 15 loci analyzed (p<0.003). The Combined Match Probability (CMP) for 15 autosomal STR was 1 in 7.89208×10-19 and the Combined Discrimination Power (CDP) was 0.9999999997. The discrimination power (DP) was especially high in D2S1338, D18S51, D19S433 and D21S11. Based on the results observed in a Dendrogram, Tikrit population was clustered with other populations, likely reflecting the historical and geographical factors. D2S1338, D18S51, D19S433 and D21S11 markers were recognized as suitable for forensic genetics analysis in Tikrit population. Also, the 15 STRs markers provide information for the studies of genetic distances between the current study and other included populations to be compared with this study.