DEVELOPMENT AND VALIDATION OF A 21-PLEX STR PANEL

Abstract Short tandem repeat (STR) analysis is the most common and informative type of DNA profiling widely used in paternity testing, missing persons' cases, and forensic applications. Several commercial kits based on STR technology were developed to meet current international standards, such as the European Standard Set (ESS) and the Combined DNA Index System (CODIS). Here, we report the development of the in-house STR panel ixMark PLUS that contains 21 markers: the 13 original CODIS STR loci with four non-overlapping loci from the expanded ESS, as well as SE33 and D6S1043, one Y-STR DYS391, and the sex-determining marker Amelogenin. The full list of markers in the panel are as follows: vWA, D16S539, CSF1PO, TPOX, D8S1179, D21S11, D18S51, DYS391, D2S441, D22S1045, THO1, FGA, Amelogenin, D5S818, D13S317, D7S820, SE33, D3S1358, D1S1656, D12S391, and D6S1043. The novel 21-plex assay ixMark PLUS includes primers, the internal size standard of 14 fragments, the allelic ladder of 241 fragments, and the matrix standard set, all designed and developed in-house. The results of developmental validation showed the kit's robustness, reliability, and suitability as a valuable addition to the current commercial kits for human DNA identification.