Jiang Lanrui, Song Mengyuan, Song Feng, Wang Shuangshuang, Zhou Yuxiang, Wang Zefei, Sun Chaoran, Yao Hewen, Zhang Zhirui, Wang Xindi, Liao Miao, Wang Yanyun, Luo Haibo
Department of Forensic Genetics, West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, 3-16 Renmin South Road, Chengdu, Sichuan Province, 610041, China.
Department of Laboratory Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan, China.
Int J Legal Med. 2025 May;139(3):1053-1062. doi: 10.1007/s00414-025-03442-0. Epub 2025 Feb 13.
Determination of the type of body fluids is highly desired in forensic investigations. Extrachromosomal circular DNA (eccDNA) is a double-stranded, circular type of nucleic acid molecule that exists outside chromosomes and is ubiquitous in eukaryotic cells, which is widely explored in clinical research. The use of eccDNA for body fluid identification has remained relatively unexplored. As such, peripheral blood, menstrual blood, semen, and saliva samples (each = 3) from healthy individuals were detected, using Circle-seq, to identify potential markers for body fluid identification. In total, 263,036 eccDNAs were identified, widely distributed throughout the genome, and most of them were within 1000 base pairs in size. The study combined eccDNA with RNA analysis in an attempt to observe the relationship between eccDNA and gene expression in healthy individuals. We performed outward PCR on selected eccDNAs using library samples and validated the predicted junction sites by Sanger sequencing. In short, this pilot study demonstrated for the first time the characterization of eccDNA profiles from four body fluids of healthy individuals. It provided a novel direction for body fluid identification. In the future, breaking the low abundance and high heterogeneity of eccDNA will lead to new possibilities in the forensic field.
在法医调查中，非常需要确定体液的类型。染色体外环状DNA（eccDNA）是一种双链环状核酸分子，存在于染色体之外，在真核细胞中普遍存在，在临床研究中得到了广泛探索。利用eccDNA进行体液鉴定的研究相对较少。因此，我们使用Circle-seq技术对健康个体的外周血、月经血、精液和唾液样本（各3份）进行检测，以确定体液鉴定的潜在标志物。总共鉴定出263,036个eccDNA，广泛分布于整个基因组中，其中大多数大小在1000个碱基对以内。该研究将eccDNA与RNA分析相结合，试图观察健康个体中eccDNA与基因表达之间的关系。我们使用文库样本对选定的eccDNA进行了外向PCR，并通过Sanger测序验证了预测的连接位点。简而言之，这项初步研究首次展示了健康个体四种体液的eccDNA图谱特征。它为体液鉴定提供了一个新的方向。未来，突破eccDNA的低丰度和高异质性将为法医领域带来新的可能性。
