This project tested the effects of regional location and seasonal characteristics on microbial-based estimates of postmortem interval (PMI) and further examined the microbiome of decaying human bone in estimating PMI during an extended postmortem period.
One goal was to determine whether changes in skin and grave soil microbial communities were similar during decomposition at three anthropological research facilities. A second goal was to determine whether seasonal variations in microbial communities associated with decomposing human cadavers were consistent among the three geographic regions. The third goal was to determine whether an examination of change in microbial community was useful for estimating PMI after active decay (extended PMI) by sampling human bone at a single anthropological research facility at the Sam Houston State University Applied Anatomical Research Center in Texas (SHSU). Project design and methods are described, including data analysis. Findings indicate that the study confirmed the findings of previous studies that demonstrated the predictable patterns of microbial community succession during PMI. The microbial communities shifted as PMI increased, with slight differences among facilities involved in the study. Overall, results suggest that PMI models can be constructed to predict PMI across multiple geographic regions. A limiting factor in producing a robust model is sample size across a broad temperature range for the training model. This report suggests that including more high-quality data sets in model training may result in more accurate predictions of test samples, at least within a season. 5 figures and a listing of 4 project publications