Circulating microRNA for the identification of forensically relevant body fluids

The development of molecular genetics-based body fluid identification methods in forensic science has become necessary to provide greater sensitivity and specificity than that obtained using conventional serological and immunological methods. Numerous studies have demonstrated the ability to identify the body fluid origin of forensically relevant biological stains using messenger RNA expression analysis. However, the length of the amplified products used in these assays may not be ideal for use with highly degraded or environmentally compromised forensic casework samples. Therefore a novel approach to body fluid identification using small RNA profiling (e.g., microRNA or miRNA profiling) was developed in an attempt to improve the success of analysis with highly degraded samples. We have identified a set of nine differentially expressed miRNAs that permit the identification of the body fluid origin of forensic biological stains and in this chapter provide the detailed procedures for performing these assays.