The Forensic Institute, 166 Buchanan Street, Glasgow, G1 2LW, UK.
Forensic Sci Int Genet. 2013 Jul;7(4):434-43. doi: 10.1016/j.fsigen.2013.03.013. Epub 2013 Apr 24.
DNA-bearing cellular material can come to be present on a surface by either direct or indirect transfer. Direct transfer includes contact, but also includes activities within the vicinity of an item that may result in the transfer of DNA directly from an individual without any contact, such as speaking, coughing, and sneezing. Indirect transfer of DNA is when DNA from an individual comes to be on an item via an intermediary surface. It is important to consider indirect transfer in the evaluation of trace DNA in casework. The term 'trace DNA' in this review refers solely to DNA that cannot be attributed to an identifiable body fluid. This review presents and considers data from trace DNA experiments to establish whether the quantity of DNA recovered from a crime stain and/or the quality of a DNA profile obtained can be used to infer the likely mechanism of transfer. The data show that varied results are obtained from apparently similar trace DNA samples, presumably due to the many factors that affect the detection of trace DNA. The nature and effect of these varying factors and the application of the data to casework is considered generally and with specific reference to DNA transfer to skin, DNA beneath fingernails, 'wearer DNA', and various contamination considerations.
带有 DNA 的细胞物质可以通过直接或间接转移而存在于表面上。直接转移包括接触，但也包括在物品附近的活动，这些活动可能导致 DNA 直接从个体转移，而无需任何接触，例如说话、咳嗽和打喷嚏。间接转移是指个体的 DNA 通过中间表面转移到物品上。在案件工作中评估痕量 DNA 时，考虑间接转移非常重要。在本综述中，术语“痕量 DNA”仅指无法归因于可识别体液的 DNA。本综述介绍并考虑了痕量 DNA 实验数据，以确定从犯罪痕迹中回收的 DNA 量和/或获得的 DNA 图谱的质量是否可用于推断可能的转移机制。数据表明，从明显相似的痕量 DNA 样本中获得了不同的结果，这可能是由于影响痕量 DNA 检测的许多因素造成的。考虑了这些变化因素的性质和影响以及将数据应用于案件工作的一般情况，并特别参考了 DNA 向皮肤、指甲下的 DNA、“佩戴者 DNA”和各种污染考虑因素的转移。
