An Investigation of the Effect of DNA Degradation and Inhibition on PCR Amplification of Single Source and Mixed Forensic Samples

The goal of this proposal is to develop methods to better understand the effect of inhibition and degradation in the recovery of DNA information from casework samples. A better understanding of inhibition mechanisms could lead to the development of more sensitive and robust crime lab protocols. Various analytical techniques (e.g., capillary electrophoresis, mass spectrometry) will be used to detect specific inhibitors in skeletal samples that have been exposed to various environmental conditions. Controlled laboratory experiments studying the effects and mechanisms of specific inhibitors (e.g., humic acid, indigo, and collagen) on DNA templates will also be performed, followed by studies using samples from adjudicated casework. The principal investigator will collaborate with scientists from the University of Tennessee Anthropology Department (for inhibition studies involving skeletal remains), the Vermont Department of Public Safety Crime Lab (for real-time PCR assays examining degradation), the Broward County Crime Lab (for examining adjudicated casework samples), and NIST (for assistance with primer design).

ca/ncf