NCJ Number
219256
Journal
Journal of Forensic Sciences Volume: 52 Issue: 4 Dated: July 2007 Pages: 891-894
Date Published
July 2007
Length
4 pages
Annotation
This paper reports on a rape case in which DNA mixture analysis was performed with an in-house cloning technique applied to mitochondrial DNA (mtDNA) fragments.
Abstract
Although the authors mainly found the rape victim's haplotype, they were able to detect the rape suspect's haplotype in two clones for HVI and in one clone for HVII. Since the midpiece of the flagellum, the part of the cell that contains mitochondria, can be lost during the differential lysis, the authors also examined the female fraction by cloning to evaluate the proportion of victim/suspect mtDNA. Unfortunately, only clones that presented the victim's haplotype were found. This case highlights the need for an optimal differential lysis protocol that will enrich the male fraction with mtDNA as well as nuclear DNA. Amplification of the HVI and HVII regions was performed for the suspect and victim reference samples and sequenced in order to determine their respective haplotypes. Amplification of the same regions from the male fraction extracted from the vaginal swab and further cloning were performed in different PCR-dedicated laboratory rooms in order to avoid contamination. Since all negative controls were clean, the HVI and HVII fragments were cloned with the homemade T/A cloning vector. Vector preparation yields enough material for 50 cloning experiments. Only plasmids that presented amplification with intensities corresponding to quantities higher than 30 ng ml were further sequenced. This procedure allows not only the quantitation of the plasmid DNA, but also quality assay by detection of DNA preparation that contains PCR-inhibitors that could make the sequencing fail. 2 tables, 1 figure, and 7 references