DNA identification of human remains has a valuable role in the field of forensic science and wider. Although DNA is vital in identification of unknown human remains, post-mortem environmental factors can lead to poor molecular preservation. In this respect, focus has been placed on DNA extraction methodologies for hard tissue samples, as these are the longest surviving. Despite decades of research being conducted on DNA extraction methods for bone and teeth, little consensus has been reached as to the best performing. Therefore, the aim of this study was to conduct a thorough systematic literature review to identify potential DNA extraction technique(s) which perform optimally for forensic DNA profiling from hard tissue samples. PRISMA guidelines were used, by which a search strategy was developed. This included identifying databases and discipline specific journals, keywords, and exclusion and inclusion criteria. In total, 175 articles were identified that detailed over 50 different DNA extraction methodologies. Results of the meta-analysis conducted on 41 articles - meeting further inclusion criteria - showed that statistically significant higher DNA profiling success was associated with solid-phase magnetic bead/resin methods. In addition, incorporating a demineralisation pre-step resulted in significantly higher profiling successes. For hard tissue type, bone outperformed teeth, and even though dense cortical femur samples were more frequently used across the studies, profiling success was comparable, and in some cases, higher in cancellous bone samples. Notably, incomplete data sharing resulted in many studies being excluded, thus an emphasis for minimum reporting standards is made. In conclusion, this study identifies strategies that may improve success rates of forensic DNA profiling from hard tissue samples. Finally, continued improvements to current methods can ensure faster times to resolution and restoring the identity of those who died in obscurity.

Bodies without names: A retrospective review of unidentified decedents at Salt River Mortuary, Cape Town, South Africa, 2010 - 2017

While human identification is a crucial aspect of medico-legal investigations, many individuals remain unidentified each year across the world. The burden of unidentified bodies is often referred to when motivating for improved methods of identification, and anatomical teaching, yet the actual burden is somewhat unclear. A systematic literature review was undertaken to identify articles that empirically investigate the number of unidentified bodies experienced. Despite the large number of articles returned, an alarmingly low number (24 articles) provided specific and empirical details on the number of unidentified bodies, demographics and trends thereof. It is possible that this lack of data is due to the variable definition of ‘unidentified’ bodies and the use of alternative terminology such as ‘homelessness’ or ‘unclaimed’ bodies. Nevertheless, the 24 articles provided data for 15 forensic facilities across ten countries of both developed and developing statuses. On average, developing countries experienced more than double (9.56%) the number of unidentified bodies when compared to developed nations (4.40%). While facilities were mandated under different legislations and infrastructures available varied greatly, the most common issue faced is the lack of standardised procedures for forensic human identification. Further to this, the need for investigative databases was highlighted. Through addressing the standardisation of identification procedures and terminology, alongside the appropriate utilisation of existing infrastructure and database creation, the number of unidentified bodies could be significantly reduced globally.

Sudden unexpected death is an upsetting event, which can remain unexplained even after post-mortem investigation. Internationally, molecular autopsies have shown to resolve up to 44% of unexplained cases; however, it is currently unclear how many of these were infants. This systematic literature review showed that significantly fewer infant cases were resolved (median: 4%) compared with cohorts of 1 to 45 years old (median: 32%). Further, no study involving indigenous African participants has yet been published. Overall, molecular autopsies hold immense value to living family members and is motivation to explore new avenues in infant cohorts.