Bacterial Community Analysis of Soil Samples Beneath Decomposing Sus scrofa Carcasses

The post-mortem interval (PMI) is the time elapsed from the time of death until the discovery of a decomposing body, which forensic scientists utilize to decipher how and when a death occurred. Much of decomposition is attributable to bacterial activity. Identifying a net change in bacterial composition throughout the PMI of a decomposing carcass helps to explain the mechanism of decomposition. Carcasses of four feral swine were placed in cages in direct sunlight, whereby soil samples were taken prior to and following seven days of decomposition. Bacterial DNA was then isolated from the soil samples and amplified via polymerase-chain reaction. Further metagenomic analysis was conducted by an outside agency using 16S ribosomal RNA (rRNA) amplicon sequencing to determine the composition of the bacterial community. A relationship between the stages of decomposition and the anatomy of bacterial communities involved was determined, which helps to elucidate the process of decomposition.