College of Science and Engineering, Flinders University, Adelaide, South Australia, Australia.
Office of the Chief Forensic Scientist, Victoria Police Forensic Services Department, Macleod, Victoria, Australia; School of Agriculture, Biomedicine and Environment, La Trobe University, Bundoora, Victoria, Australia.
Forensic Sci Int Genet. 2024 Nov;73:103130. doi: 10.1016/j.fsigen.2024.103130. Epub 2024 Aug 28.
The heightened sensitivity of DNA typing techniques, paired with the extensive use of trace DNA in forensic investigations, has resulted in an increased need to understand how and when DNA is deposited on surfaces of interest. This study focussed on the transfer, persistence, and prevalence of trace DNA in a single occupation of an office space by an intruder, when all contacts made during occupation and for the two hours prior and post occupation were known. The extent to which DNA could be recovered from contacted/not contacted surfaces was investigated. This study investigates the impacts of these movements and use of an office space when the duration of occupancy, surface contact histories and shedder status of participants are known. Contacts were documented and surfaces in the office space were targeted for sampling. Categories were set for target sampling that included different types of contact. Direct and indirect DNA transfer was detected in 55 % and 6 % of samples, respectively. Contactless DNA transfer was detected in 0.5 % of samples. The owner was observed as the sole/major/majority contributor in 77 % of the samples and as minor contributor in 10 % of samples. The intruder was observed as the sole/major/majority contributor in 14 % of samples and as the minor contributor in 16 %. An increased number of contacts increased the relative DNA contribution of the individual making the contact, however, not all observed direct contacts resulted in detectable DNA transfer. The outcome of this study will aid in better sample targeting strategies and contribute to the pool of data assisting in the development of activity level assessments.
DNA 分型技术的灵敏度提高，加上痕量 DNA 在法医学调查中的广泛应用，使得人们越来越需要了解 DNA 是如何以及何时沉积在感兴趣的表面上。本研究集中于在一个入侵者单独占用一个办公室空间的情况下，当知道占用期间以及占用前后两小时内的所有接触情况时，痕量 DNA 的转移、持久性和普遍性。研究了从接触/未接触表面可以回收多少 DNA。本研究调查了当占用时间、表面接触历史和参与者的脱落者状态已知时，这些运动和使用办公空间的影响。记录了接触情况，并针对办公空间中的表面进行了采样。目标采样的类别包括不同类型的接触。直接和间接的 DNA 转移分别在 55%和 6%的样本中被检测到。在 0.5%的样本中检测到无接触 DNA 转移。在 77%的样本中，所有者被观察为唯一/主要/多数贡献者，在 10%的样本中被观察为次要贡献者。在 14%的样本中，入侵者被观察为唯一/主要/多数贡献者，在 16%的样本中被观察为次要贡献者。接触次数的增加增加了进行接触的个体的相对 DNA 贡献，但并非所有观察到的直接接触都导致可检测的 DNA 转移。本研究的结果将有助于更好的样本靶向策略，并为协助开发活动水平评估的数据池做出贡献。
