RESUMO
Semen stain identification is one of the crucial tasks for collection of criminal evidence by forensic techniques. Substances such as DNA and RNA contained in semen stains can serve as a source of personalized evidence targeting the suspect. Therefore, semen stain identification is vital to inferring the case attributes and the facts of the crime. The conventional methods of forensic stain identification focus on the detection of specific-function protein and/or high-content protein, such as alkaline phosphatase and PSA. Although the specificity of such protein markers is relatively high, these methods yield a limited rate of success for several factors, including poor stability, low sensitivity of the target protein, and possible subjectivity of the performer. In order to overcome these limitations, new technologies such as Raman spectroscopy, mass spectrometry for protein markers, sperm-specific aptamer, mRNA, microRNA, and DNA methylation assays have been studied and recommended by many investigators. These new technologies are paving a new ground for personalized trace analysis and even for detection of over-timed specimens.