Abstract
<jats:p>The article is devoted to a comprehensive analysis of the molecular genetic profile of saliva as one of the most promising and technologically accessible sources of biological information in forensic personal identification. Saliva is considered a multilevel biological system that includes epithelial cells, leukocytes, extracellular nucleic acids, protein fractions, enzymatic complexes, and microbial communities, which ensures high diagnostic value even with minimal sample volumes and partial degradation of traces recovered from environmental objects. Modern methodological approaches to DNA extraction, purification, and quantitative assessment are analyzed, including the possibilities of STR profiling of degraded samples and the use of tissue-specific mRNA markers to confirm the origin of biological traces, differentiate them from other body fluids, and increase the evidential value of forensic examinations. Particular attention is paid to epigenetic strategies based on the analysis of CpG methylation patterns, which make it possible to distinguish salivary material from blood, semen, and sweat, obtain approximate information about the donor’s biological age, and assess the influence of environmental factors. Prospects for microbiome analysis are discussed as an additional level of individualization reflecting oral health status, dietary habits, hygiene practices, and chronic pathological processes. The necessity of strict compliance with procedures for collection, transportation, storage, and laboratory processing is emphasized in order to prevent degradation, contamination, and interpretative errors. It is concluded that the integration of DNA, RNA, epigenetic, and microbiome data forms a multilevel molecular portrait of an individual, expands the capabilities of forensic identification, and provides a scientific basis for standardizing protocols and establishing specialized forensic biological databases. The practical significance of the study lies in increasing the accuracy of expert conclusions, reducing the probability of false matches, optimizing laboratory workflows, accelerating investigations, and introducing interdisciplinary approaches into the training of forensic specialists and the development of unified quality standards for national registers of biological traces used for future personal identification and expert decision-making.</jats:p>