Forensic Context

A study in human samples demonstrated that the miR-451a is a blood-specific microRNA marker, showing high expression in blood and low expression in saliva, which was sufficient to distinguish between these fluids [Omelia et al. DOI:10.1016/j.ab.2012.024]. A subsequent systematic analysis of 605 human body fluid samples confirmed the miR-451a is overexpressed in mature red blood cells, showing high expression in both peripheral and menstrual blood, and identified it as a key component of an optimal four-marker panel that, when combined with a kernel density estimation classifier, achieved highly accurate and robust forensic body fluid identification [Liu et al. DOI:10.1093/bib/bbaa324]. Further research established that the expression ratio of the miR-451a to miR-21-5p provides a robust forensic strategy, where a ratio above 0.929 identifies blood and a ratio above 10.201 specifically distinguishes peripheral blood from menstrual blood with 100% sensitivity and specificity, an identification unaffected by donor variables or sample degradation [Wang et al. DOI:10.1016/j.fsigen.2021.102654].