Performance comparison of MiSeq forensic genomics system and STR-CE using control and mock IED samples

Abstract

The adoption of next-generation sequencing (NGS) for forensic purposes are on the rise. Studies have shown that NGS can replace or supplement conventional STR-CE system, but direct comparisons between them are still lacking, especially on improvised explosive device evidence. Here, we directly compared the performances of the MiSeq Forensic Genomics System (ForenSeq kit on the MiSeq FGx instrument utilizing the Universal Analysis Software) with the Identifiler Plus kit on the ABI3130/3500 instrument. Two dilution series (500 to 8pg) and touch DNA on mock IED substrates were used. Profile qualities were highly correlated between the two systems. The MiSeq system was equally sensitive to the STR-CE system for single-source samples. High quality profiles were obtained from touch DNA samples on various IED substrates, even at sub–100pg concentrations. Due to the sheer number and variety of loci typed, higher likelihood ratios were obtained with the MiSeq profiles and more adjunct information, such as Y-STRs and identity SNPs, are available. The intra-STR sequence variants also allowed unambiguous designation of stutters and true alleles. These suggest that the MiSeq system can be used for touch DNA samples from IED substrates. Further evaluations of the MiSeq system using mixtures, inhibited samples, and real IED casework samples are ongoing.