Assessing the forensic implications of DNA degradation for PMI estimation using comet assay: A systematic review

Abstract

Accurate post-mortem interval estimation is crucial in forensic investigations, providing essential information for criminal cases. Traditional techniques frequently encounter inaccuracies stemming from environmental and individual variables. The comet assay is a very sensitive technique that detects DNA damage, which has emerged as a promising tool for assessing DNA degradation. This approach can serve as a molecular clock for post-mortem interval estimation, offering a more precise and reliable means of determining the time since death in forensic cases. This systematic review was registered with the International Prospective Register of Systematic Reviews (PROSPERO-CRD42024554907) and adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) standards. An extensive electronic database search, including Google Scholar, Embase, Web of Science, PubMed, and Scopus was conducted to find the studies utilizing the comet assay for DNA degradation measurement in post-mortem interval estimation. Two reviewers independently screened and extracted data from eligible studies. The risk of bias tool from the Systematic Review Centre for Laboratory Animal Experimentation was used to evaluate the quality of the research. All six studies fulfilled the inclusion requirements, employing the comet assay on various animal tissues. Studies show a clear relationship between post-mortem interval and degradation of DNA, with varying rates depending on tissue type and environmental factors. The comet assay can detect DNA fragmentation effectively, but difficulties arise from variations in study designs and methodologies. Despite its promise for estimating post-mortem interval, the standardization of protocols is needed to improve reliability and applicability in forensics. Future research should establish standardized methods and explore environmental impacts on DNA degradation.