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Project

Development of a forensic molecular clock to determine time of death and blood trace deposition time

The time and date of a person’s death are two of the major questions police detectives and investigative judges ask a forensic pathologist as it provides a specific time frame in which the investigators can base their further investigations on. The current time of death estimation techniques produce large error ranges as environmental and endogenous factors have to be taken into account. The most widely accepted and accurate model is based on the deep rectal temperature that decreases at a rate of 1-2 °C/h until ambient temperature is reached. The 95% confidence interval increases with post mortem interval: ±2.8h before 18h after death, ±7h after 28h and ±4.5h in between. Too large prediction intervals for time of death estimation are of little use to the investigators though at present no tools are available to limit the ranges offered. Misjudging the time of death can eventually lead to wrongful convictions and wrongful acquittals in court and narrowing the time of death error ranges to a minimum would therefore have a substantial impact on police investigation worldwide.

The internal biological clock or circadian rhythm is a 24-hour pattern that is synchronized to the environment and influences internal behaviors such as hormone levels, RNA expression and body temperature.  These circadian biomarkers have the potential to be used as a forensic clock in order to estimate the time of death of an individual since the production of these products ceases after death. It could provide a unique snapshot of exactly the time a person died. Endocrine, metabolome and transcriptome markers will be analyzed in blood samples of deceased individuals with a known time of death. The blood samples will be collected from forensic cases, medical autopsies and the emergency care unit (UZ Leuven) with strict exclusion criteria to eliminate individuals with shifted rhythms. The biomarkers with robust circadian patterns will be used in a prediction model. Afterwards, a targeted RNA-Seq assay will be developed containing only the markers in the prediction model. The complete targeted assay (including a limited set of RNA transcripts, metabolites and hormones) will be tested on an independent test-set from individuals with a known ToD.

Date:1 Sep 2015 →  20 Apr 2021
Keywords:forensic molecular clock, time of death, blood trace deposition time
Disciplines:Criminology, Other chemical sciences, Other biological sciences, Forensic medicine
Project type:PhD project