The appropriateness of analysing some known micro-RNAs to detect the presence of semen in old stains

Recently microRNAs (miRNAs) have gained notoriety for having revealed useful biomarkers. The advantage of using microRNAs as biomarkers lies in their ease of use and the accuracy with which they can be measured as well as their extreme tissue specificity. Furthermore, these small molecules are exceptionally stable in laboratory treatments, unlike larger RNA molecules such as messenger RNA. In the forensic field, the use of microRNAs to confirm biological evidence has become a powerful tool of crucial importance for the reconstruction of a crime scene. Semen can provide significant evidence in some types of crime, particularly sexual assault. However, a diagnosis of sperm is often difficult for several reasons, such as trace degratheir ease of use and the accuracy with which they can be measured as well as their extreme tissue specificity. Furthermore, these small molecules are exceptionally stable in laboratory treatments, unlike larger RNA molecules such as messenger RNA. In the forensic field, the use of microRNAs to confirm biological evidence has become a powerful tool of crucial importance for the reconstruction of a crime scene. Semen can provide significant evidence in some types of crime, particularly sexual assault. However, a diagnosis of sperm is often difficult for several reasons, such as trace degradation and the presence of azoospermia, which are still present when using morphological, immunological and enzymatic methods. Recent studies show that the use of micro-RNAs overcomes both the problem of degradation (due to their high resistance to exogenous factors) and the absence of spermatozoa in azoospermic individuals. In this study, some semen-specific microRNAs (miR-10a-5p, miR-888-5p, miR891a-5p, miR135a-5p, miR135b-5p) on old semen stains were tested to assess their suitability in forensic casework. The expression of this set of markers was evaluated using a miRCURY LNA Universal RT microRNA PCR System. LNA technology showed interesting properties for molecular hybridization, including enhanced specificity in allele-specific PCR and could be used to overcome the difficulties of studying very short sequences. We concluded that the cellular specificity of the studied microRNA set makes it possible to identify the presence of semen in old stains with high specificity and consequently with high probative value in a court of justice.