Evaluation of DNA profiles obtained from deceased individuals at Salt River Mortuary (South Africa)

Abstract

ABSTRACTDNA profiling is a valuable tool for human identification, particularly when deceased individuals cannot be identified by traditional methods. Annually, at Salt River Mortuary (SRM), ~320 bodies remain unidentified following post-mortem investigation. While much research has been conducted into DNA profiling on living individuals, relatively little has focused on suitability within the deceased population, and thus this formed the focus of this research. Buccal cells were collected from deceased infants (n = 38) and adults (n = 37) at SRM, with a time interval between death and sample collection of 1 – 887 days. Control blood samples were obtained from a subset of participants. Samples were processed using the PowerPlex ESI 16 System or Y23 System (Promega). Full DNA profiles were obtained from all blood samples. Following optimization, 74.7% and 18.7% of buccal swabs yielded full and partial profiles respectively, while 6.7% failed completely. Upon analysis, partial and failed profiles were significantly associated with the DNA degradation index from cotton swabs (p < 0.001), but not with time between death and sample collection (p = 0.16). These results indicate that full DNA profiles can be obtained long after death. It is hypothesized that factors influencing degradation (e.g. decomposition) may contribute to failure. Overall, further research is required to identify factors influencing DNA profile quality.