Evaluation of mRNA Markers for Estimating Blood Deposition Time

RNA analysis provide insight into diseases, molecular identification of body fluids and mechanisms leading to death and might develop into a valuable tool for identification of the cause of death in forensic pathology. Further potential uses are the determination of the age of wounds and the post-mortem interval. In this proof-of-concept pilot study clarifies and explains principles, applications and methods by offering a comprehensive and complete overview of using mRNA markers for estimating blood deposition time which can help to evaluate the time of the crime in forensic RNA work. The study presented in this thesis aimed to estimate the time passed since blood stains found in the crime scene by calculating the time of deposited blood using particular mRNA markers and unravelling one of the principles of at what time – when during the day or night a biological evidence was left at the scene – by applying the insights from circadian biology to some open forensic cases. By analyzing 4 candidate mRNA markers expression in peripheral blood samples collected from 29 health males. Blood samples were collected from healthy persons for the duration of the 24 hours’ day/night interval under four different groups, i.e. night/early, morning early morning/morning, morning/afternoon and afternoon/night. This study identified 2 mRNAs with statistically significant expression rhythms which are MKNK2 and PER 3. It’s found that, in general mRNA-based estimation of time categories was less accurate. The value of mRNA was demonstrated for blood deposition timing and introduced a statistical model for estimating day/night time categories based on molecular biomarkers, which shall be further validated with additional samples in the future.