Trends in DNA Aanalysis to Determine Postmortem Interval: A Systematic Lilterature Review

Forensic taphonomy is a recently popular field within forensic anthropology with limited research in the Central Great Plains. Given decomposition varies by region, more studies must be done to understand aspects of decomposition in this region. However, it is one of the most important subfields of forensic anthropology since determining postmortem interval (PMI) is extremely important to successfully identifying a missing individual if other indications of who the individual is are nonexistent. In this study, a systematic literature review was conducted to answer what trends are seen in research being done for using DNA to determine PMI, and what methods should be used to use DNA to determine PMI. This study can be used as an indicator for what areas in this field could use more research, as well as pointing out ways to standardize data collection and reporting. The ‘preferred reporting items for systematic literature reviews and meta-analyses’ (PRISMA) (Xiao and Watson 2019; Finnaughty et al. 2023) were used to guide the methodology in conducting the systematic literature review. Articles were found for the systematic literature review (SLR) by searching seventeen different combinations of certain keywords on PubMed’s database. Out of 1,577 total articles found, 866 unique articles were included in the SLR for screening. After each screening the article number went from 866 to 82 to 24 articles that were included in data collection. Demographics of each study were collected from each article. For methods in determining PMI, specimen DNA was the most common (50%) method to use followed by microbiological methods (33.3%). The leading sampling methods for PMI were soil samples (37.5%) followed by swab samples (20.8%). Although collected, not much was done for the DNA yield of each article, since there was no consistency within the reporting of quantification between various articles. Future directions in this research include further examination and standardization of reporting quantified DNA and methods to determine PMI; further studies using other microbial methods such as bacteria and fungi that are common in decomposition; gathering this methodology and standardizing it for a field-accessible method that is simple to use for those that are not specialized in the field of taphonomy. Advisor: Elizabeth S. Clausing