NCJ Number
246363
Journal
Forensic Science International: Genetics Volume: 7 Issue: 1 Dated: January 2013 Pages: 136-142
Date Published
January 2013
Length
7 pages
Annotation
This study tested the performance of a DNA-based assay that determines whether a sample is semen-based through detection of semen-specific methylation patterns in five genomic loci.
Abstract
The testing of the performance of the assay - called DSI-semen (DNA source identifier-semen) - determined that it is a bona fide confirmatory test for semen. The kit was tested on 135 samples of semen, saliva, venous blood, menstrual blood, urine, and vaginal swabs and the identification of semen vs. non-semen was correct in all cases. In order to test the assay's applicability in "real-life" situations, 33 actual casework samples from the forensic biological lab of the Israeli police were analyzed, and the results were compared with microscopic examination performed by Israeli police personnel. There was complete concordance between both analyses except for one sample, in which the assay identified semen but no sperm was seen in the microscope. This sample likely represents true semen because sperm cells were detected from an adjacent sample from the same garment; therefore, in this case the assay appears to be more sensitive than the microscopic examination. The assay, which aims to replace microscopic examination for semen, can easily be integrated by forensic laboratories and can be automated. 3 tables, 3 figures, and 19 references