Danio rerio as a model for post-mortem interval estimation based on methylation levels

Abstract Objective The post-mortem interval (PMI) describes the period of time elapsed since death. A precise estimation of PMI has a strong impact in a crime investigation; however, it becomes a complex task due to the influence of intrinsic and extrinsic factors. There are several methods for PMI determination including pathological, biochemical and entomological. Those methodologies have low precision and several practical limitations leading to the emergence of genetic-molecular methods based on degradation of nucleic acids. DNA methylation is a sufficiently stable and time-related epigenetic modification, making it useful for the development of a method to determine PMI. Thus, the methylation levels of a model organism – zebrafish – were analysed since the moment of death, in order to contribute to create a robust model for the PMI estimation.Results In this study, we evaluated the variation in global methylation levels and at the promoter region of EDARADD gene during 6 post-mortem intervals. An increase of global methylation levels in the initial post-mortem intervals was observed, followed by an abrupt decrease until 48h post-mortem. Followed by the amplification of EDARADD’s promoter region by q-PCR and HRM analysis, it was possible to differentiate samples according to relative PMI.