Microbiome Research for Forensic Science

Microbes are ubiquitous and diverse, yet microbial communities exhibit repeatable patterns across many ecosystems and sample types. It is likely that some aspects of microbial ecology may be useful as forensic tools. For example, we know that microbes play an important role in decomposition of cadavers and we are exploring the use of microbial succession during decomposition to estimate the time since death and as an indicator for locating unknown (clandestine) graves. Additionally, we are exploring the potential use of relationships between the bacteria of the built environment (e.g. Sloan House Project above) and the bacteria of their occupants for use as trace evidence.

We are currently working on characterizing microbial community changes associated with decomposing corpses (contact: Jessica Metcalf). In conjunction with a number of forensics collaborators and under the auspices of a grant from the National Institutes of Justice, we are using a mouse model system in a controlled laboratory system to understand how bacterial and microbial eukaryotic communities change during decomposition and whether it is repeatable across many replicates. Our goals are to 1) determine whether bacterial and microbial eukaryotic, in particular fungal, decomposer communities change in a predictable manner as corpse decomposition proceeds 2) determine whether decomposer communities change the endogenous soil community in detectable ways and therefore may be useful for locating graves of unknown location and 3) determine whether decomposer communities are universal or source-specific by characterizing variation in these communities across soil types. Recently, we determined that postmortem microbial community changes are dramatic, measurable, and repeatable in a mouse model system, allowing postmortem interval (time since death) to be estimated within approximately 3 days over 48 days (Metcalf et al., 2013). Our results provide a detailed understanding of bacterial and microbial eukaryotic ecology within a decomposing corpse system and suggest that microbial community data can be developed into a forensic tool for estimating the postmortem interval and locating clandestine graves.