Genetic Structure of the Iraqi Population at 15 STRs and the Consequent Forensic Applications

Abstract

1061 individuals were sampled from the cities of Anbar, Baghdad, Basra, Diyala, Najaf, and Wasit in Iraq and typed for 15 forensic STRs to explore the genetic structure of Iraq and develop a forensic DNA database. Analyses found that Iraq is similar to other countries in the Middle East, particularly Iran and Turkey, and is more similar to Europe than either Asia or Africa. Iraq is genetically diverse; a clustering algorithm was used to infer the number of genetic clusters in the population and the best fit was eight genetic clusters. Baghdad provides a good representation of the rest of country while Anbar is the most genetically distinct. This may be because Anbar is the only city sampled in a Sunni-dominant region. Although genetic structure differs significantly between the cities, most of the genetic differentiation is between genetic clusters rather than cities. These loci had an average heterozygosity of 0.779, homozygosity of 0.221, polymorphism information content of 0.77, power of discrimination of 0.927, and power of exclusion of 0.563. At these loci, a matching genotype will occur, on average, in 1 in 8.152 x 1017 individuals. For paternity tests, the average paternity probability for a matching profile is 99.9997%. For both measures, this can be taken as an exact match. These loci are appropriate for use in forensic and paternity testing for this population.