Institute of Applied Genetics, Department of Forensic and Investigative Genetics, University of North Texas Health Science Center, Fort Worth, TX 76107, USA.
Int J Legal Med. 2012 Nov;126(6):851-61. doi: 10.1007/s00414-012-0743-1. Epub 2012 Jul 15.
Studies of DNA transfer have focused largely on the transfer of sloughed off epithelial cells from individuals' hands. This research examines primary, secondary, and tertiary transfer events involving DNA originating from saliva, a commonly encountered body fluid. More routine human behaviors were simulated to evaluate transfer, and the effects of drying time, moisture, and surface composition were investigated. The results agree with previous findings which indicate that the presence of moisture, as well as a smooth nonporous surface as the primary substrate, increases the efficiency of transfer. Previous transfer studies have found that the last individual to come into contact with an item is usually the major contributor to the resulting DNA mixture, unless conditions are simulated in which a "good shedder" serves as the primary depositor and a poor shedder serves as the secondary depositor. The results of this study indicate that when saliva is the source of the transferred DNA, the primary depositor is often the major contributor. These findings suggest that shedder status is less relevant with regard to touch DNA samples in a forensic setting and emphasize the need for caution when analyzing such samples.
DNA 转移的研究主要集中在个体手上脱落的上皮细胞的转移上。本研究检查了涉及源自唾液的 DNA 的原发性、继发性和三级转移事件，唾液是一种常见的体液。模拟了更常规的人类行为来评估转移，并研究了干燥时间、水分和表面成分的影响。研究结果与先前的发现一致，表明存在水分以及作为主要基质的光滑无孔表面会提高转移效率。先前的转移研究发现，与物品最后接触的人通常是导致最终 DNA 混合物的主要贡献者，除非在模拟条件下，“良好脱落者”作为主要沉积者，而“不良脱落者”作为次要沉积者。本研究的结果表明，当唾液是转移 DNA 的来源时，主要沉积者通常是主要贡献者。这些发现表明，在法医环境中，脱落者状态与接触 DNA 样本的相关性较小，并强调在分析此类样本时需要谨慎。
