AUTHORS: Darren M. Wood, Dr. Amy B. Welsh - West Virginia University
ABSTRACT. Crimes against culturally and economically important wildlife vary both spatially across a landscape and temporally. While officer response times to these crimes and ensuing collection of evidence may also vary spatiotemporally, exposure of evidence to environmental factors including changing temperatures and UV radiation may degrade evidence below qualities and quantities suitable for DNA analysis. Additionally, materials from which evidence is collected from may contribute to DNA degradation. Aliquots of blood from white-tailed deer (Odocoilius virginianus), were collected in EDTA K2 blood tubes to prevent blood clotting and stored at 4°C until use. A 40 µL volume of blood (equivalent to 1 drop) was placed on separate pieces of 4 mm plastic and 1.6 mm steel (materials common to white-tailed deer biological evidence collection). Blood droplets were exposed in a 35°C incubator for 24 and 48 hour time periods. Genomic DNA from each exposed sample and a non-exposed control was extracted and purified using a Qiagen DNeasy blood and tissue kit. DNA quantity was measured through Real-Time PCR using a white-tailed deer specific primer. While no significant differences (a = 0.5) were found within material groups exposed for 24 and 48 hour time periods (Steel: P = 0.43, Plastic: P = 0.49) as well as between the different materials after 24 hours (P = 0.31), significant differences were found between the groups after 48 hours of exposure (P = 0.01). Additionally, differences in DNA quantity were found between all exposed groups and the non-exposed control. Results from this preliminary study indicate the importance of exposure time and material for timely biological evidence collection, but also the need to determine further environmental factors that may inhibit downstream DNA analysis.
