Department of Forensic Medicine and Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-752, South Korea.
Int J Legal Med. 2013 Jan;127(1):35-43. doi: 10.1007/s00414-012-0719-1. Epub 2012 Jun 1.
Recent advances in whole-genome epigenetic analysis indicate that chromosome segments called tissue-specific differentially methylated regions (tDMRs) show different DNA methylation profiles according to cell or tissue type. Therefore, body fluid-specific differential DNA methylation is a promising indicator for body fluid identification. However, DNA methylation patterns are susceptible to change in response to environmental factors and aging. Therefore, we investigated age-related methylation changes in semen-specific tDMRs using body fluids from young and elderly men. After confirming the stability of the body fluid-specific DNA methylation profile over time, two different multiplex PCR systems were constructed using methylation-sensitive restriction enzyme PCR and methylation SNaPshot, in order to analyze the methylation status of specific CpG sites from the USP49, DACT1, PRMT2, and PFN3 tDMRs. Both multiplex systems could successfully identify semen with spermatozoa and could differentiate menstrual blood and vaginal fluids from blood and saliva. Although including more markers for body fluid identification might be necessary, this study adds to the support that body fluid identification by DNA methylation profiles could be a valuable tool for forensic analysis of body fluids.
全基因组表观遗传分析的最新进展表明，称为组织特异性差异甲基化区域（tDMR）的染色体片段根据细胞或组织类型显示不同的 DNA 甲基化模式。因此，体液特异性差异 DNA 甲基化是体液鉴定的一个很有前途的指标。然而，DNA 甲基化模式容易受到环境因素和衰老的影响而发生变化。因此，我们使用年轻和老年男性的体液研究了精液特异性 tDMR 中的与年龄相关的甲基化变化。在确认了体液特异性 DNA 甲基化图谱随时间的稳定性之后，使用甲基敏感限制性内切酶 PCR 和甲基化 SNaPshot 构建了两种不同的多重 PCR 系统，以分析 USP49、DACT1、PRMT2 和 PFN3 tDMR 中特定 CpG 位点的甲基化状态。这两种多重系统都可以成功地识别含有精子的精液，并且可以区分月经血和阴道液与血液和唾液。尽管可能需要包括更多的用于体液鉴定的标记物，但本研究增加了支持通过 DNA 甲基化图谱进行体液鉴定可以成为体液法医分析的有价值工具的证据。
