Application of Next Generation Sequencing Technology for the Analysis of Mixed DNA Samples

The new NGS platforms developed allow fast, easy, and most importantly the ability to analyze hundreds of loci in a single run simultaneously, enabling the analysis of mixtures with SNP markers. In this study, DNA samples obtained from 6 different individuals; 2-females and 4-males, were examined. These 6 individuals are formed in double groups artificially prepared in various ratios and a total of 20 samples and 124 SNP loci were analyzed with the HID-Identity panel and Ion-Torrent-PGM platform. To compare the results with the conventional method, which is the capillary electrophoresis platform, the same samples were analyzed by capillary electrophoresis method using the AmpFlSTR®Identifiler®STR Kit. In the SNP analyses performed with the Ion Torrent platform, in all 1 : 1 and 1 : 3 ratios, the average number of readings of minor alleles was obtained at a very successful level. Although the average number of readings decreased as expected from 1 : 10 ratio, the rate of minor allele detection was 21.7%, even at the ratio of 1 : 50. When the results of the SNP analysis were compared with the STR analysis; it was determined that SNP analyzes obtained more successful results compared to STR analysis when the amount of DNA belonging to the minor allele in the mixtures was low. In this study, it has been determined that the HID-Identity panel, which is compatible with the Ion-Torrent-PGM platform and analyzes 124 SNP loci, gives fast, easy, and reliable results and can be successfully used to analyze mixtures.