Long-term room temperature preservation of corpse soft tissue: an approach for tissue sample storage

Fragments of human psoas muscle were exposed to three different environmental conditions for diverse time periods at room temperature. Storage conditions included: (a) a preserving medium consisting of solid sodium chloride (salt), (b) no additional substances and (c) garden soil. DNA was extracted with proteinase K/SDS followed by organic solvent treatment and concentration by centrifugal filter devices. Quantification was carried out by real-time PCR using commercial kits. Short tandem repeat (STR) typing profiles were analysed with 'expert software'.DNA quantities recovered from samples stored in salt were similar up to the complete storage time and underscored the effectiveness of the preservation method. It was possible to reliably and accurately type different genetic systems including autosomal STRs and mitochondrial and Y-chromosome haplogroups. Autosomal STR typing quality was evaluated by expert software, denoting high quality profiles from DNA samples obtained from corpse tissue stored in salt for up to 365 days.The procedure proposed herein is a cost efficient alternative for storage of human remains in challenging environmental areas, such as mass disaster locations, mass graves and exhumations. This technique should be considered as an additional method for sample storage when preservation of DNA integrity is required for PCR-based DNA typing.Disaster victim identification (DVI) represents one of the most difficult challenges in forensic sciences. This complex task is usually approached within a multidisciplinary context [1-4]. In addition to the conventional identification criteria applied, including visual recognition, odontology, dactyloscopy and antemortem information, DNA-based identification represents, after 20 years of successful use, the gold standard for assisting in DVI [5]. Tissue preservation and subsequent DNA typing have become essential techniques, especially in disasters involving body fragmentation.DNA purification from soft tissue is