NCJ Number
236679
Journal
Forensic Science International: Genetics Volume: 5 Issue: 5 Dated: November 2011 Pages: 479-483
Date Published
November 2011
Length
5 pages
Annotation
In this study, the transfer and persistence of DNA under the fingernails after an act of digital penetration were examined.
Abstract
Acts of aggression and defense during sexual assaults often lead to transfer of DNA from victim to assailant. Of sexual assault cases recorded by the FSS between 2005 and 2010, approximately 20 percent and 3 percent involved digital penetration of the victim's vagina or anus, respectively. Of the 309 cases where digital penetration was alleged, a suspect was arrested within approximately 1 day in 135 cases and fingernail samples were taken in 101 of these cases. In this study the transfer and persistence of DNA under the fingernails after an act of digital penetration were examined, (a) to assist investigators in determining whether to obtain such samples initially and (b) to assist evaluators in assessing the evidential value of female DNA profiles post analysis. Full female profiles were obtained from all swabs collected at 0 and 6h after digital penetration, indicating that female DNA was always transferred and persisted in the short term. Furthermore, full female profiles were produced from three-quarters of samples collected after 12h whilst mixed profiles were produced in the majority of samples taken after 18h. The analysis of several variables indicated that hand washing had a significant effect on the persistence of female DNA profiles. (Published Abstract)