Laser Microdissection Separation of Pure Spermatozoa Populations from Mixed Cell Samples for Forensic DNA Analysis

This DNA R&D project focuses on development of a method for simultaneous identification and recovery of sperm in sexual assault evidence mixtures using Laser Microdissection (LMD). LMD can directly dissect and collect pure cell populations for immediate DNA isolation without contamination from intermixed foreign cells. The cells of interest are circumscribed through the computer software image and cut by laser ablation, after which they are collected by gravity into a microcentrifuge tube below the stage for further investigation. LMD can provide a solution to cases where mixed genotypes are unresolved or sample analysis is not pursued due to an insufficient number of target cells. The goal of this project is to demonstrate the effectiveness of LMD and develop protocols for simultaneous identification and recovery of sperm in cellular mixtures that permits better separation of minute traces of male sexual assailant DNA from victims DNA. ca/ncf