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

在调查犯罪和恐怖袭击时，法医DNA分析在确定生物证据来源方面发挥着至关重要的作用。DNA分析通过比较个人特有的DNA图谱将证据与个人联系起来。然而，核酸分析不仅将一个人与一件证据联系起来，而且将其与犯罪本身联系起来的潜力迄今尚未得到充分利用和评价。特别是，证据被存放在犯罪现场的确切时间还不是科学痕迹分析的一部分。但是，关于痕迹年龄的信息，或者更准确地说，痕迹沉积后的时间（TsD），对于确定证据在调查过程中的相关性至关重要。如果痕迹沉积发生在犯罪的估计时间点，相关性高，而较老/较新的痕迹的相关性低，因为它们的沉积可能与犯罪本身无关。为了弥补当前分子痕迹分析的这一差距，我们将：- 利用RNA、DNA和蛋白质分子结构的时间依赖性变化-使用新的大规模并行测序和质谱法获得这些分子的全局降解模式-联合收割机结合法医RNA方面的各自专业知识，在德国和瑞士进行DNA和蛋白质分析，以全面概述每个分子作为标记物的潜力-开发标记物阵列，用于可靠地确定生物痕迹的沉积时间（TsD）-开发TsD确定的预测模型。提供所有三种类型的分子（DNA、RNA和蛋白质）的完整概述以及评估不同分析设置中结果的再现性是至关重要的。这就是为什么两个独立实验室之间的合作至关重要。确定TsD是目前法医工具箱中迫切需要的补充，将有助于调查人员和法院评估生物痕迹的相关性。它提高了对真正肇事者定罪的可靠性，并使被错误指控的人迅速恢复正常生活。

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.