Application of Duplex Droplet Digital PCR Detection of miR-888 and miR-891a in Semen Identification.

Objectives: To establish a system for simultaneous detection of miR-888 and miR-891a by droplet digital PCR (ddPCR), and to evaluate its application value in semen identification.

Methods: The hydrolysis probes with different fluorescence modified reporter groups were designed to realize the detection of miR-888 and miR-891a by duplex ddPCR. A total of 75 samples of 5 body fluids (including peripheral blood, menstrual blood, semen, saliva and vaginal secretion) were detected.

Screening and evaluation of endogenous reference genes for miRNA expression analysis in forensic body fluid samples.

MicroRNA (miRNA)-based methods for body fluid identification are promising tools in the practice of forensic science. The selection of appropriate endogenous reference genes as normalizers for the relative quantification of miRNA expression levels using quantitative reverse transcription-polymerase chain reaction (RTqPCR) is essential to avoid errors and improve the comparability of miRNA expression level data among different body fluids. In this study, small RNAs were isolated from individual donations of five forensically relevant body fluids (peripheral blood, menstrual blood, saliva, semen and vaginal secretions).

A new strategy for distinguishing menstrual blood from peripheral blood by the miR-451a/miR-21-5p ratio.

Distinction between menstrual blood and peripheral blood is vital for forensic casework, as it could provide strong evidence to figure out the nature of some criminal cases. However, to date no single blood-specific gene, including the most variable microRNAs (miRNAs) could work well in identification of blood source. In this study, we developed a new strategy for identification of human blood samples by using the copy number ratios of miR-451a to miR-21-5p based on 133 samples, including 56 menstrual blood and 47 peripheral blood, as well as 30 non-blood samples of saliva (10), semen (10) and vaginal secretion (10).