Would the real allele please stand up? Compiling DNA artefacts for the GlobalFiler PCR amplification kit – a South Australian approach

ABSTRACT

This article presents a compendium of DNA artefacts observed using the GlobalFiler and GlobalFiler Express PCR kits (ThermoFisher Scientific) during DNA reference profile assessment at Forensic Science SA (FSSA). The data are currently used to assist with the interpretation of GlobalFiler DNA evidence profiles encountered in the course of routine case work at FSSA. Over 1000 reference profiles have passed observation by reference DNA run readers. An artefact was considered confirmed if it was observed in five or more individual reference samples and could be confirmed upon re-PCR. Artefacts were documented in the following two categories: (1) those with a location independent of true allelic products and (2) those with a location relative to a true allelic product. The artefacts observed were positioned within and outside of allelic designations and were typically less than 1% of the closest allelic product. Artefacts reported here are observed from reference samples only. Their causes are largely unknown and warrant further investigation. Post-developmental artefacts may be encountered due to storage and handling conditions. As such, continued monitoring of reference samples for low level artefacts is warranted.