NCJ Number
209746
Journal
Journal of Forensic Sciences Volume: 50 Issue: 3 Dated: May 2005 Pages: 579-581
Date Published
May 2005
Length
3 pages
Annotation
This study examined barriers to DNA sequencing of the HV1 and 2 regions of the mitochondrial DNA (mtDNA) following differential lysis.
Abstract
Forensic identification of an unknown offender in a murder case involved the sequencing of the HV1 and 2 regions of the mtDNA in order to gain information about the ethnic origin of the offender. DNA was extracted from spermatozoa after differential lysis. Results yielded mtDNA sequences that were identical to the mtDNA sequences of the victim. The goal of the current study was to determine if this match was a coincidence or if the match was the result of a technical limitation of the testing procedure. Vaginal swabs were taken from test persons 24 hours post coitum; the swabs were treated as casework samples except they were washed 1 extra time to ensure no carry-over with vaginal cells. Results showed that in cases with complete separation of sperm and female cells, it was impossible to obtain a mtDNA sequence for the sperm due to the loss of the flagellum and mid-piece during the first lysis step, followed by a concomitant loss of the sperm’s mitochondria. The findings suggest that, in regard to the murder case, the minor carry-over of female cells to the sperm fraction was responsible for the sequencing match. Figures, references