Present day inbreeding does not forbid the forensic utility of commonly explored STR loci: A case study of native Qataris

Abstract

Allele frequency distribution of 15 short tandem repeat (STR) loci (D8S1179, D21S11, D7S820, CSF1PO, D3S1358, TH01, D13S317, D16S539, D2S1338, D19S433, vWA, TPOX, D18S51, D5S818, and FGA) was studied in a sample of 120 unrelated native Qatari population using the AmpFISTR® Identifiler kit (Applied Biosystems, Foster city, CA, USA). All loci met Hardy-Weinberg expectations and there was no evidence for linkage disequilibrium between any of the marker pairs. The most discriminating locus was D2S1338 with a power of discrimination (PD) of 0.969, while the lowest one was TPOX, yet with a PD of 0.821. For all the 15 loci, the combined PD and the combined power of exclusion (PE) were respectively 0.99999999 and 0.99999744. Thus the probability of finding two individuals bearing an identical 15 locus DNA profile is one in 108 native Qatari subjects and this surpasses largely the present day Qatari natives consisting of around 3.5 × 105 individuals. The results of this study demonstrate the usefulness and reliability of the AmpFISTR® Identifiler kit for individual identification in forensic studies in the native Qatari population, despite the current practice of high inbreeding.