NCJ Number
214495
Journal
Journal of Forensic Sciences Volume: 51 Issue: 3 Dated: May 2006 Pages: 574-579
Date Published
May 2006
Length
6 pages
Annotation
This report describes an improved method of obtaining sperm from cotton swabs in rape kit analysis by means of enzymatic digestion.
Abstract
The findings support the hypothesis that enzymatic digestion of cotton swabs by using cellulase can increase the number of sperm cells obtained from mock sexual assault samples compared with buffer methods alone; however, as the drying time for the samples increased, the concentration of Aspergillus niger cellulase required also increased. The comparison of enzyme digestion with conventional differential extraction (DE) in obtaining sperm cells from cotton swabs showed an equivalent removal of sperm cells; however, enzyme digestion provided the added benefit of intact epithelial cell removal. The preliminary testing of higher activity cellulases from Trichoderma reesei and Trichoderma viride showed even greater improvement. These findings show the potential of the enzymatic digestion method as an alternative to the DE procedure in forensic DNA analysis. In order to mimic vaginal epithelial cells expected on casework rape sample swabs, epithelial cells from the mouth cavity (buccal swabs) were collected onto sterile cotton swabs and allowed to dry for a minimum of 3 days at room temperature. All buccal swabs and semen samples were obtained from voluntary donations from healthy females and males. The procedure for cell extraction from cotton swabs is described in detail, along with the determination of cell recovery. 6 figures, 1 table, and 29 references