Forensic validation of the Genplex SNP typing system—Results of an inter-laboratory study

Abstract We present data from a multi-laboratory validation study of the Genplex typing system [C. Phillips, et al., Evaluation of the Genplex SNP typing system and a 49plex forensic marker panel, Forensic Sci. Int.: Genet. 1 (2) (2007) 180–185.] (Applied Biosystems), which interrogates a subset of 48 SNPs selected from the panel of 52 previously developed for forensic analysis by the SNP for ID consortium [J.J. Sanchez, et al., A multiplex assay with 52 single nucleotide polymorphisms for human identification, Electrophoresis 27 (9) (2006) 1713–1724.], plus amelogenin. The Genplex technology was developed through modification of the SNPlex™ system (also Applied Biosystems) and utilises oligo-ligation of PCR products followed by probe hybridisation to generate dye-labeled, allele-specific oligonucleotides that are detected with capillary electrophoresis. We compare the success rate of Genplex in typing 55 samples in three laboratories with results obtained from STR typing of the same samples using Powerplex ® 16 (Promega) and SGMPlus ® (Applied Biosystems). The sample set was chosen to mimic extracts encountered in forensic situations and includes low concentration and degraded material as well as mixtures. We demonstrate that the Genplex technique provides a significantly higher success rate than STR-based methods when typing degraded DNA and is also capable of mixture detection up to a level of 1 in 10.