School of Forensic Sciences, Center for Health Sciences, Oklahoma State University, Tulsa, OK, United States.
School of Forensic Sciences, Center for Health Sciences, Oklahoma State University, Tulsa, OK, United States.
Forensic Sci Int Genet. 2019 Mar;39:103-108. doi: 10.1016/j.fsigen.2018.12.004. Epub 2018 Dec 21.
The value of RNA analysis in the forensic laboratory as one means of identifying the nature of biological evidence of forensic relevance has been well established. The degradation of RNA in dried body fluid stains has also been an area of forensic interest because of the potential to estimate the age of a stain recovered from a crime scene. Here we describe a qPCR assay that demonstrates it is possible to estimate the age of bloodstains with reasonable accuracy. The 5'-3' qPCR assay exploits the observation the 5' end of an mRNA transcript degrades in dried stains faster than the 3' end. This differential degradation pattern can be followed with a qPCR assay that quantifies ∼90 bp amplicons produced from the 5' and 3' ends of 4 transcripts chosen from the transcriptome of blood because of their degradation kinetics, determined initially using RNA sequencing. Statistical analysis of degradation kinetics suggests, depending upon the age of the sample, the age of blood stains can be accurately estimated to within 2-4 weeks for stains less than 6 months of age and 4-6 weeks for stains 6 months to 1 year old.
RNA 分析在法医实验室中作为鉴定法医学相关生物证据性质的一种手段的价值已经得到充分确立。由于有可能估计从犯罪现场回收的污渍的年龄，因此干燥体液污渍中 RNA 的降解也是法医关注的一个领域。在这里，我们描述了一种 qPCR 测定法，该测定法证明可以合理准确地估计血斑的年龄。5'-3'qPCR 测定法利用了这样一个观察结果，即 mRNA 转录本的 5'端在干燥的污渍中比 3'端更快降解。这种差异降解模式可以通过 qPCR 测定法来跟踪，该测定法定量了来自血液转录组的 4 个转录本的 5'和 3'端产生的约 90bp 扩增子，这是由于其降解动力学最初使用 RNA 测序确定的。降解动力学的统计分析表明，根据样本的年龄，可以准确估计年龄小于 6 个月的血斑的年龄，在 6 个月至 1 岁的血斑的年龄为 4-6 周。
