Efficiency of Buccal DNA Sampling Device in the Mortuary

Identification of forensic DNA samples by short tandem repeat (STR) profiling is currently an essential component of criminal investigations and can aid in linking perpetrators to crimes as well as identifying missing individuals or unidentified remains. In South Africa, recent amendments to legislation have allowed for the mandatory acquisition of reference DNA samples from certain offenders in order to populate the new National Forensic DNA Database. A novel method for the collection of buccal samples, the EasiCollect device, has been proposed to facilitate the collection of these DNA samples, replacing blood collecting devices as the standard method of DNA collection. Subsequently, this device has been introduced into South African state mortuaries to assist in the identification of deceased individuals. In order to ascertain if this device is suitable for use in the postmortem setting, an investigation was performed to compare the main methodology currently utilised within South African mortuaries, namely femoral blood transferred to ‘Fast Technology for Analysis of nucleic acids' (FTA) cards, and buccal cells obtained using the EasiCollect device. DNA yields and STR genotyping results were compared between the two collection methods in thirty deceased individuals. Buccal samples provided a significantly greater DNA yield than blood samples, while no significant difference was observed between the qualities of the sample types as measured by the 260/280 nm ratio. Full STR profiles were obtained from all blood and buccal samples, with amplification efficiency showing limited DNA degradation and PCR inhibition in these samples, and only 3% of samples giving potentially disputable results. Numerous issues surrounding the collection of blood samples, however, indicated that this method is not optimal for use in the mortuary, with the EasiCollect device providing a more practical and robust method for the collection of DNA samples in the mortuary.