Evaluation of different methods for DNA extraction from human burnt bones and the generation of genetic profiles for identification

Abstract

Bone exposure to heat in the presence of moisture breaks the phosphodiester bonds of the backbone, leaving sheared DNA in bone cells. This also limits the possibility of generating a complete profile of the victim. With the increasing incidence of fire outbreaks over the past few years, a paradigm shift to establish identity has been observed, from morphological identification of victims to STR profiling. For this study, 10 bone samples were taken from burnt human bodies that were recovered from different fire outbreak scenes. The DNA from these burnt human tissues was isolated using four different extraction methods: the organic extraction method, the total demineralisation method, the Qiagen kit method, and the Chelex extraction method. STR profiles of victims were generated on a genetic analyser using an AmpFlSTR Identifiler® Plus Kit and analysed on Gene Mapper ID-X. DNA isolated from bones using the total demineralisation extraction method and organic extraction method was of the highest quality due to the efficient removal of inhibitors. DNA obtained using these two methods successfully generated the STR profiles of the victims. The quality of isolated DNA obtained through the Qiagen kit was comparatively low, but STR profiles of the victims were successfully generated. The Chelex kit failed to extract good quality DNA of high quantity from the burnt bones, encountering inhibition in all samples at varying degrees. This study concludes that total demineralisation and the Qiagen kit are sophisticated and reliable methods to obtain a good yield of DNA from burnt human bones, which can be used for the identification of victims.