Giovanelli Alexandre, Grazinoli Garrido Rodrigo, Rocha Alípio, Hessab Tatiana
Departamento de Polícia Técnico-Científica do Rio de Janeiro, Instituto de Pesquisa e Perícia em Genética Forense, Rio de Janeiro, Brazil.
J Forensic Sci. 2022 Mar;67(2):707-711. doi: 10.1111/1556-4029.14932. Epub 2021 Nov 2.
Several methods of DNA collection are used in places or objects related to crimes, the most common being the use of swabs. However, it is known that the efficacy of touch DNA recovery can be affected by collection devices and surfaces. The aim of this work was to evaluate the efficiency of three different types of swab in recovering touch DNA collected from different parts of a vehicle. The following swabs were tested: PurFlock swab (Puritan, USA), 4N6FLOQSwabs™ (Copan S.p.A., Italy), and cotton swab (Labor Import). The experiments were carried out in the same vehicle, using the gearshift knob, the parking brake lever, and the steering wheel as support for the collection of touch DNA. Swabs showed significant differences in the amount of DNA recovered (Hc = 53.52; p < 0.05) and in the rate of allele amplification (Hc = 24.3; p < 0.05). The results indicated a greater DNA recovery efficiency by PurFlock swab, followed by cotton, and then 4N6FLOQSwabs™. However, there was no significant difference among the surfaces analyzed. PurFlock swab was more efficient for recovering donor alleles than the others (cotton and 4N6FLOQSwabs™), especially for small DNA amounts. This swab was, therefore, suitable for collections in vehicles involved in crime. Furthermore, this study highlights the need to assess different materials and methods of collection of biological samples, considering collection, extraction, and amplification.
在与犯罪相关的场所或物品上，人们使用多种DNA采集方法，其中最常用的是使用拭子。然而，众所周知，接触式DNA提取的效率会受到采集设备和表面的影响。这项工作的目的是评估三种不同类型的拭子在从车辆不同部位采集的接触式DNA提取方面的效率。测试了以下几种拭子：PurFlock拭子（美国Puritan公司）、4N6FLOQSwabs™（意大利Copan S.p.A.公司）和棉拭子（Labor Import公司）。实验在同一辆车内进行，使用换挡旋钮、驻车制动杆和方向盘作为采集接触式DNA的支撑物。拭子在回收的DNA量（Hc = 53.52；p < 0.05）和等位基因扩增率（Hc = 24.3；p < 0.05）方面存在显著差异。结果表明，PurFlock拭子的DNA回收效率更高，其次是棉拭子，然后是4N6FLOQSwabs™。然而，所分析的表面之间没有显著差异。PurFlock拭子在回收供体等位基因方面比其他拭子（棉拭子和4N6FLOQSwabs™）更有效，尤其是对于少量DNA。因此，这种拭子适用于涉及犯罪车辆的采集。此外，本研究强调了在考虑采集、提取和扩增的情况下，评估生物样本不同采集材料和方法的必要性。
