Identification of mRNA expression patterns in the human blood thanatotranscriptome: “Dead, but not entirely”

Purpose: RNA analysis of post-mortem tissues, or thanathotranscriptomics, has become a topic of interest in forensic science due to the essential information it can provide in forensic case investigations. Several studies have previously investigated the effect of death on gene transcription, but it has never been conducted with samples of the same individual. Methods: For the first time, a longitudinal mRNA expression analysis study was performed with post-mortem human blood samples from individuals with a known time of death. Results: The results reveal that, after death, two clearly differentiated groups of up- and down-regulated genes can be detected. Pathway analysis suggests active processes, rather than passive degradation, are the source of early post-mortem changes of gene expression in blood. In addition, a generalised linear model with an elastic net restriction predicted post-mortem interval with an RMSE of 4.88 hours. Conclusions: Although promising, the forensic relevance of the model is currently limited and should be further improved in more extended studies. RNA-Seq analysis of 54 post-mortem human blood samples