Micro-RNA evaluation, specification, and stabilization study in mixed/non-mixed body fluids as a specific molecular marker

Body fluids are frequently recovered by forensic investigators from crime scenes, and their identification is an important aspect of forensic case analysis. Determining the type and origin of human fluids recovered at a crime scene will give essential information for crime scene reconstruction by establishing a link between sample donors and actual criminal activity. The expression levels of microRNAs (miRNAs) such as miR-10b, miR-135b, miR-16, miR-126, miR-124-3p, and miR-372 in seminal fluids, blood, vaginal fluid stains, and their mixture, were measured using a quantitative real-time PCR technique. Using SNORD-47 as a reference gene, the target genes' identification and stability were assessed. miR-10b and miR-135b were expressed at higher levels in seminal fluids stains than in vaginal secretion stains; miR-124-3p and miR-372 were expressed at higher levels in vaginal stains than in seminal fluids stains; miR-16 and miR-126 were expressed at a higher level in bloodstains than in both seminal fluids and vaginal stains, and six miRNAs were expressed in seminal fluids/vaginal/blood mix stains. In conclusion, the results indicate that the expression levels of miR-10b and miR-135b (seminal fluids), miR-124-3p and miR-372 (vaginal secretion), and miR-16 and miR-126 (blood) were higher in these samples compared to the housekeeping gene SNORD-47.