Development of a one-tube extraction and amplification method for DNA analysis of sperm and epithelial cells recovered from forensic samples by laser microdissection

Laser microdissection can be used in forensic casework to isolate specific cell types from mixtures of biological samples. Extraction of DNA from selected cells is still required prior to STR amplification. Because of the relatively pristine nature of the recovered cells, laser microdissection is more sensitive than more traditional methods of DNA analysis, theoretically resulting in DNA profiles from less cellular material. A one-tube extraction and amplification method minimises loss of DNA through liquid transfers and reduces the potential for contamination events occurring. In this paper, the development of a one-tube method for the effective extraction of DNA from laser microdissected sperm and epithelial cells is described. The performance of the in-house method was compared to that of a commercial DNA extraction kit for extraction of DNA from sperm and the downstream compatibility with STR amplification was determined for both sperm and epithelial samples. Full Identifiler™ profiles after 28 amplification cycles were obtained from as few as 15 epithelial cells and 30 sperm.