Current Status and Future Perspectives of Human Saliva Identification in Forensic Science

DNA typing is a powerful tool in forensic science; however, its evidentiary value depends on clarifying the origin and context of DNA deposition. Within the hierarchical structure of criminal proof, DNA typing typically addresses the sub-source level and requires the identification of the associated body fluid to strengthen its relevance. Among the body fluids found at crime scenes, including blood, semen, and saliva, saliva is particularly significant because of its high retention rate and broad applicability beyond violent or sexual crimes. It can be recovered from bite marks, cigarettes, food remnants, envelopes, and even vehicle components and may appear through indirect transfer, such as coughing or sneezing. Saliva-derived DNA often plays a major role in forensic identification, offering strong potential for individualization. This review explores the properties of human saliva, current detection methods, and future perspectives, emphasizing its critical role in enhancing the interpretative power of DNA evidence.