NCJ Number
223164
Journal
Canadian Society of Forensic Science Journal Volume: 41 Issue: 1 Dated: March 2008 Pages: 29-37
Date Published
March 2008
Length
9 pages
Annotation
This study assessed the feasibility of using bacterial DNA profiling in distinguishing between soil samples in forensic investigations.
Abstract
The low number of common terminal restriction fragments (TRFs) found at all points along each transect in the study; the small, variable cluster sizes; and the presence of nonclustering samples showed considerable difference in the soil bacterial DNA profiles on a relatively small scale. This small-scale variability may cause problems if forensic "matching" of soil DNA profiles is attempted, unless the precise location from which the soil sample was originally taken could be identified. Therefore, the authors urge caution in the application of TRF length polymorphism (TRFLP) analysis to the "matching" of soil DNA profiles. A more feasible approach may be to use characteristic features of the DNA profile in order to identify possible sites/ecosystems from which the soil could have originated. In the current study, soil samples were collected from the same three ecosystems as in the authors' earlier study: a field, a forest, and a dune system in Northwest England. Within each of these sites, samples from 2 m horizontal soil transects randomly chosen were collected in the late summer of 2003. Surface soil samples approximately 5 cm x 5 cm x 5 cm were collected at 20-cm intervals along each transect, resulting in 11 samples per transect. The soil scoop was cleaned with alcohol between each sampling. The samples were air-dried, homogenized, sieved, and stored in plastic bags at 120 degrees C. All samples were then treated in the same way. The description of the methods used addresses DNA extraction, DNA amplification and bacterial community TRFLP analysis, and statistical analysis. 2 figures, 1 table, and 20 references