Journal of Cold Case Review
Volume 1, Issue 1, July 2015 Pg 26
An Official Publication of The American Investigative Society of Cold Cases
By Suzanna Ryan, MS
New Collection Technique - the M-Vac System
In order to get an informative DNA profile, whether it be through autosomal or Y chromosome analysis, first the analyst must be able to collect the DNA from the substrate. Traditional methods for collecting DNA from a particular sample or substrate include swabbing, cutting, or taping. A new method of sample collection is the The M-Vac system. The M-Vac is a wet vacuum collection system designed to be used on forensic evidence. Studies have shown that this system is able to collect more DNA than traditional methods (in one study, up to 180X more epithelial cell DNA was collected with the M-Vac system as compared to swabbing). In addition, the M-Vac system has shown to be useful in collecting DNA from large areas and is even able to collect additional DNA from samples that have already been swabbed.
Research studies on the M-Vac system conducted at UC Davis show that the M-Vac was able to collect male DNA from the shirts of female volunteers after males had merely grabbed the shirts. The M-Vac was compared to traditional swabbing methods and it was shown that M-Vac system was able to collect nearly 10 times the amount of male DNA than the swabbing method in one experiment. The M-Vac system was also shown to be useful in collecting male saliva from female volunteer’s skin even after the female had showered. While swabbing also yielded some male DNA from the skin of females after showering, the benefit of the M-Vac is that large areas are able to be sampled in a single sample, versus the comparatively smaller areas that may be sampled through swabbing alone.
A full copy of the journal is available at the AISOCC website.