Soil can be of tremendous evidentiary value in forensic investigations. Historically, soil evidence has been analyzed based on physical or chemical characteristics; however, microbial analysis has recently emerged as a possible way to better characterize soil samples. Within any given soil sample there are hundreds or thousands of species of microorganisms, each differing in abundance. This variation can potentially be assayed, producing a unique and comparable microbial "fingerprint" for questioned and known samples. The aim of this research was to examine the effectiveness of real-time PCR in the analysis of forensic soil samples. This was accomplished by collecting soil from four different locations around mid-Michigan over a one year period, extracting bacterial DNA, and targeting the 16S rRNA gene of different bacterial groups known to vary in abundance based on soil type. Several soil characteristics were examined including uniqueness among habitats, changes in bacterial communities over time, and the level of heterogeneity within a habitat. Multivariate statistical analysis was performed to determine the significance of each characteristic examined. Results showed that some habitats could be differentiated from one another using ADONIS and NMDS. Habitats had little variability at different depths; however the Agricultural Field and Marsh showed significant temporal variability. Given this, most habitats could still be distinguished from one another in a pairwise manner, which more truly reflects a forensic situation.
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