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Time Radically Alters Ex Situ Evidentiary Soil 16S Bacterial Profiles Produced Via Next-Generation Sequencing

NCJ Number
Journal of Forensic Sciences Volume: 63 Issue: 5 Dated: February 2018 Pages: 1356-1365
Date Published
February 2018
10 pages
This study placed soils collected from multiple habitats on evidence items that were samples over time, and then bacterial profiles were generated via next generation sequencing of the 16S rRNA locus.

Previous research has revealed the potential of soil bacterial profiling for forensic purposes; however, investigators have not thoroughly examined fluctuations in microbial profiles from soil aged on evidence. In the current study, bacterial abundance charts and nonmetric multidimensional scaling plots provided visual representation of bacterial profiles temporally, while supervised classification was used to statistically associate evidence to a source. The ex situ evidence soils displayed specific, consistent taxonomic changes as they aged, resulting in their drift in multidimensional space, but never toward a different habitat. Ninety five percent of the 364 evidentiary profiles statistically classified to the correct habitat, with misclassification generally stemming from evidence type and increased age. Ultimately, understanding bacterial changes that occur temporally in ex situ soils should enhance their use in forensic investigations. (publisher abstract modified)

Date Published: February 1, 2018