Ali Darya, van Oorschot Roland A H, Linacre Adrian, Goray Mariya
College of Medicine and Public Health, Flinders University, Bedford Park, South Australia, Australia.
Office of the Chief Forensic Scientist, Victoria Police Forensic Services Department, Macleod, VIC, Australia.
Int J Legal Med. 2025 May;139(3):965-981. doi: 10.1007/s00414-024-03351-8. Epub 2024 Nov 7.
"Shedder status" describes the inherent variation between individuals to leave touch DNA on a surface through direct contact. Depending on the amount and quality of DNA or cellular deposition, individuals are typically deemed high, intermediate, or low shedders. Although many shedder tests have been described, variability in study design and categorisation criteria has limited the ability of researchers to accurately compare results, as well as accrue the necessary population data. As activity level reporting becomes more common, the need for reliable and standardised testing increases. To assess reproducibility, this study compared shedder status data generated by six participants using three different shedder tests, as modified from the literature. This involved DNA quantification and profiling of a handprint made on a glass plate, DNA quantification and profiling of a grip mark made on a plastic conical tube, and cell scoring of a Diamond™ Dye-stained fingermark. All participants washed and dried their hands fifteen minutes before each deposit. To assess the impact of behaviour on shedder designation, participants either refrained from activity or went about their daily tasks during this wait. The shedder status of participants changed between tests, as DNA-based testing often generated lower shedder statuses than cell scores. Further, when different categorisation methods were applied to a single test, intra-person variability increased as the number of shedder designations increased from two (low/high) to five (low/low-intermediate/intermediate/intermediate-high/high). Moving forward, the utilisation of a single shedder test and standardised categorisation criteria is needed to employ shedder testing in forensic casework.
“脱落者状态”描述了个体之间通过直接接触在表面留下微量DNA的内在差异。根据DNA或细胞沉积的数量和质量，个体通常被分为高、中、低脱落者。尽管已经描述了许多脱落者测试，但研究设计和分类标准的差异限制了研究人员准确比较结果以及积累必要人群数据的能力。随着活动水平报告变得越来越普遍，对可靠和标准化测试的需求也在增加。为了评估可重复性，本研究比较了六名参与者使用三种根据文献修改的不同脱落者测试所产生的脱落者状态数据。这包括对在玻璃板上留下的手印进行DNA定量和分析、对在塑料锥形管上留下的握痕进行DNA定量和分析，以及对用钻石™染料染色的指纹进行细胞评分。所有参与者在每次沉积前15分钟洗手并擦干。为了评估行为对脱落者分类的影响，参与者在等待期间要么避免活动，要么进行日常任务。参与者的脱落者状态在不同测试之间有所变化，因为基于DNA的测试通常产生的脱落者状态低于细胞评分。此外，当将不同的分类方法应用于单个测试时，随着脱落者分类数量从两种（低/高）增加到五种（低/低-中/中/中-高/高），个体内部的变异性增加。展望未来，在法医案件工作中采用脱落者测试需要使用单一的脱落者测试和标准化的分类标准。
