Toenails as an alternative source material for the extraction of DNA from decomposed human remains.

The DNA identification of decomposed human remains for coronial investigations at the Victorian Institute of Forensic Medicine routinely requires the retrieval and processing of a bone sample obtained from the deceased. Bone is a difficult sample type to work with as it requires surgical removal from the deceased, refrigerated storage, and additional processing steps prior to DNA analysis in comparison to other samples types such as buccal swabs or blood stains. In an attempt to overcome the issues posed by bone, a DNA extraction method utilising toenails as an alternate source material was optimised and trialled. Two DNA extraction methods were optimised for digestion of toenail material, with the method utilising the QIAGEN DNA Investigator Kit selected for a casework trial. Single source DNA profiles, matching those of the conventional samples taken, were obtained for toenail samples collected from 28 of 30 coronial cases available for this study. Of these, 26 toenail samples produced full profiles. Although the overall DNA profile quality from the toenails was less than that of the conventional sample, the profiles from toenails met the reporting requirements for identification. Based on the results obtained, the Victorian Institute of Forensic Medicine will be implementing toenails as the primary sample type for collection from decomposed remains when blood is not a suitable sample type.

Post mortem sampling of the bladder for the identification of victims of fire related deaths.

In a coronial setting a deceased person must be formally identified. It is difficult to identify a deceased person when their physical features are disrupted and identification by visual means cannot occur. In the absence of visual identification, the confirmation of identity of a deceased person relies on the scientific comparison of information obtained post mortem with ante mortem information. The ante mortem information may include dental and medical records, fingerprints, and DNA profiling. For cases involving incinerated remains, this traditionally requires the collection of blood, muscle or bone samples from the deceased (depending on the severity of the burns) for DNA analysis and subsequent comparison to a reference sample for kinship determination. Following on from work conducted during the DVI response to a plane crash in Papua New Guinea in 2011, a study has been performed examining the viability of utilising material obtained from bladder swabs in deaths associated with fires. Twenty-eight cases were analysed during 2012 with deaths occurring in motor vehicle and aviation accidents, as well as house fires, homicides and from self-immolation. Bladder and conventional (blood, muscle or bone) samples were subjected to DNA analysis and compared. Our findings demonstrate that the bladder samples all gave DNA of sufficient quality for DNA profiling. This easily obtained sample (when available) can be now recommended in the scientific identification process of fire affected deceased persons.