This dissertation confirms that bacterial succession on skeletal remains can be used to predict long-term postmortem submersion interval in both freshwater lakes and rivers.
This dissertation reports on a research project in which the author had the goals of examining differences in both the degradation of skeletal DNA and the microbiome inhabiting bone in freshwater aquatic environments. At each location, the author submerged five porcine ribs and scapulae in 10” x 10” cages. Bone collections were gathered between November 2016 and November 2018, along with water samples from the level of the submerged material. The author evaluated microbial changes and performed site-specific analyses to determine differences among water, rib, and scapula samples. To determine how bone DNA was affected by prolonged submersion, a subset of samples underwent extraction based on the number of accumulated degree days (ADD), using both organic and phenol-chloroform and ChargeSwitch® gDNA Plant Kit before being amplified and separated with a genetic analyzer. Results suggested that a peak presence and percent complete profiles were significantly among ADD and between bone types, and regardless of extraction method and submersion site, ribs should be prioritized as they preserve recoverable DNA for longer periods of time and generate more complete (short tandem repeat) STR profiles in aquatic environments.
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