Traces of life's experiences: Epigenetics (DNA methylation) in forensics

Abstract

Since the development of methylation-based diagnostic biomarkers, the application of DNA methylation in forensic investigation is also rapidly gaining ground. DNA methylation patterns are established during early embryonic development and are influenced by both genetic and environmental factors like diet, age, stress, socioeconomic status, and habitat. Identification of differentially methylated regions (DMRs) which differ between tissues or phenotypes can be targeted for forensic applications. Tissue-specific methylation differences can be used for accurate identification of body fluid/ tissue source found at a crime scene. Agespecific methylation changes in repetitive genomic regions have been used to develop epigenetic clocks for age estimation. DNA methylation patterns differeven between monozygotic twins and can assist with the challenge of their identification. Recent development of whole genome methylation analysis platforms like Illumina whole genome methylation bead chips and single-cell reduced bisulfite sequencing has opened the doors for large-scale survey of methylation differences in both CpG islands and non-CpG regions. Future research could predict an individual's social behavior and activities by applying DNA methylation indicators. Advancements in DNA methylation analysis for forensics will complement the current STR analysis and provide robust inferences for forensic evidence and human identification.