Detection of Mutations in Short Tandem Repeats (STRs) Loci in Paternity Testing in Romanian Population

In forensic genetics, mutation analysis for different short tandem repeat (STR) loci is important for paternity and maternity testing. The aim of this study is determining the most frequent loci with mutations in a population of 743 individuals in western Romania in 246 kinship cases. These include 240 paternity and 6 maternity tests analyzed at the Laboratory of Forensic Genetics, Victor Babes University of Medicine and Pharmacy, Timisoara, Romania. The study was conducted between January 1, 2017, to January 1, 2020. The study aims to analyze the mutation rates for 15 autosomal markers used in this type of testing. The following loci were included in our study: D3S1358, D8S1179, D18S51, D21S11, FGA, TH01, vWA, CSF1PO, D7S820, D13S317, D16S539, D2S1338, D19S433, TPOX, D5S818.

For the reference samples, we used saliva collected on buccal swabs from all individuals. Salivary DNA was quantified on the 7500 real-time PCR equipment (Thermo Scientific, USA). Further, amplification of the DNA samples was performed on a ProFlex PCR System (Thermo Scientific, USA) using Identifiler Plus PCR Am-plification kit (Thermo Scientific, USA). Fragment analysis was performed on the 3500 Genetic Analyzer (Thermo Scientific, USA). The genetic profiles were generated by GeneMapper ID-X software version 1.4 (Thermo Scientific, USA).

The mutation events in paternity testing were observed in 10 out of the 15 analyzed loci: D21S11, D18S51, D16S539, D8S1179, FGA, D2S441, D19S433, D2S1338, D3S1358, D5S818 and vWA. Paternal mutations were more frequent (63%) than maternal mutations (37%).

The results confirm that the mutation rate in paternity tests are more frequent during paternal meiosis compared to maternal.