Body fluid identification at crime scenes is essential for reconstructing the events of the crime, providing key evidence to assist in determining the perpetrator, and, in some cases, the victim. Currently, a variety of presumptive and confirmatory tests exist to detect the main body fluids, blood, semen, and saliva. However, this task can be difficult when encountering trace levels, mixtures, or uncommon body fluids such as vaginal fluid or menstrual blood. A number of recent studies have explored the possibility of using DNA methylation to distinguish between body fluids, based on tissue-specific differentially methylated regions (tDMRs). Additional markers, such as non-coding RNAs, have also been utilized based on their stability and tissue-specificity. Many of these studies point to the possibility of developing assays to simultaneously detect various body fluids at the same time. This chapter will review the current state-of-the-art of the applications of epigenetics to body fluid identification, particularly DNA methylation and non-coding RNAs, including advantages and limitations, and their future applicability to forensic casework.
