Determination of the Time since Deposition (TsD) of biological crime scene traces

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In the investigation of crime and terrorist attacks, forensic DNA analysis plays a crucial role in identifying the source of biological evidence. DNA analysis links evidence to a person by comparing DNA profiles which are specific to individuals. However, the potential of nucleic acid analysis to linking a person not only to a piece of evidence but to the crime itself, is hitherto not fully exploited and evaluated. Particularly, the exact time point at which evidence has been deposited at a crime scene is not yet part of scientific trace analysis. But information on the age of a trace, or, more precisely, the time since deposition (TsD) of traces would be crucial for the determination of the relevance of the tevidence in the investigative process. If trace deposition happened at the estimated time point of the crime, the relevance is high while the relevance of older/younger traces is low because their deposition might not be related to the crime itself.To bridge this gap in current molecular trace analysis, we will:- exploit time-dependent changes in the molecular structure of RNA, DNA and proteins- use novel massive parallel sequencing and mass spectrometry to obtain global degradation patterns of these molecules- combine respective expertise in forensic RNA, DNA and protein analysis in Germany and Switzerland to provide a comprehensive overview of each molecule`s potential as marker - develop a marker array for reliable determination of the time since deposition (TsD) of biological traces- develop a prediction model for TsD determination.For the success of this project, it is crucial to provide a complete overview of all three types of molecules (DNA, RNA, and proteins), and to assess the reproducibility of results in different analytical set-ups. This is why a collaboration between two independent laboratories is crucial. Determination of TsD is an urgently needed addition to the current forensic toolbox and will aid investigators and courts of justice in assessing the relevance of biological trace. It leads to higher reliability in the conviction of true perpetrators as well as fast rehabilitation of the wrongfully accused.