Menchhoff Sydney I, Solomon April D, Cox Jordan O, Hytinen Madison E, Miller Marilyn T, Cruz Tracey Dawson
Department of Forensic Science, Virginia Commonwealth University, Richmond, Virginia, USA.
Jefferson Parish Sheriff's Office Regional DNA Laboratory, Harvey, Louisiana, USA.
Forensic Sci Res. 2020 Aug 3;7(1):61-68. doi: 10.1080/20961790.2020.1792079. eCollection 2022.
Due to recent improvements in forensic DNA testing kit sensitivity, there has been an increased demand in the criminal justice community to revisit past convictions or cold cases. Some of these cases have little biological evidence other than touch DNA in the form of archived latent fingerprint lift cards. In this study, a previously developed optimised workflow for this sample type was tested on aged fingerprints to determine if improved short tandem repeat (STR) profiles could be obtained. Two-year-old samples processed with the optimised workflow produced an average of approximately five more STR alleles per profile over the traditional method. The optimised workflow also produced detectable alleles in samples aged out to 28 years. Of the methods tested, the optimised workflow resulted in the most informative profiles from evidence samples more representative of the forensic need. This workflow is recommended for use with archived latent fingerprint samples, regardless of the archival time.Key pointsThe use of the optimised workflow on aged archived latent fingerprint (ALFP) lift card samples (aged 2-28 years) improves the number of STR alleles recovered, providing more discriminatory STR profiles than those processed using the traditional workflow.Interpretable STR alleles can be detected from ALFP lift card samples stored as long as 28 years when the optimised procedures are followed.The use of individual laboratory-sterilised tools for sample preparation and the addition of a re-purification step with Centri-Sep columns in the recommended optimised workflow seem to limit the ability to detect low-level secondary DNA sources.
由于法医DNA检测试剂盒灵敏度最近有所提高，刑事司法界对重新审查过去的定罪或悬案的需求增加。其中一些案件除了存档的潜在指纹提取卡形式的接触DNA外，几乎没有生物证据。在本研究中，对一种先前开发的针对此类样本类型的优化工作流程在陈旧指纹上进行了测试，以确定是否可以获得改进的短串联重复序列（STR）图谱。与传统方法相比，采用优化工作流程处理的两年期样本每个图谱平均多产生约五个STR等位基因。优化工作流程还在长达28年的陈旧样本中检测到了可检测的等位基因。在所测试的方法中，优化工作流程从更能代表法医需求的证据样本中产生了信息量最大的图谱。无论存档时间多长，建议将此工作流程用于存档的潜在指纹样本。要点在陈旧的存档潜在指纹（ALFP）提取卡样本（2至28年）上使用优化工作流程可增加回收的STR等位基因数量，比使用传统工作流程处理的样本提供更多具有鉴别力的STR图谱。按照优化程序操作时，从存储长达28年的ALFP提取卡样本中可检测到可解释的STR等位基因。在推荐的优化工作流程中，使用单独的实验室消毒工具进行样本制备以及添加使用Centri-Sep柱的重新纯化步骤似乎会限制检测低水平次要DNA来源的能力。
