Home » Articles posted by mvacjb2014 (Page 24)
Author Archives: mvacjb2014
An Investigation of Touch DNA Collection Methods from Clothing: Traditional Cutting Techniques Versus a Wet Vacuum System
An Investigation of Touch DNA Collection Methods from Clothing: Traditional Cutting Techniques Versus a Wet Vacuum System
by Wander, Marc John, M.S., UNIVERSITY OF CALIFORNIA, DAVIS, 2014, 52 pages; 1565737
Abstract:
This study explored an innovative method for recovering a male offender’s touch DNA deposited on the external side of a cotton t-shirt worn by a female. Traditional cutting procedures were compared, in parallel, to a novel wet vacuum system, called the M-Vac®. This investigation compared these two collection methods to discover which method resulted in a higher yield of DNA, and also examined the relative amounts of male and female DNA obtained from clothing worn by a female and grabbed by a male, with the intent of mimicking an assault. The collected DNA was extracted and then quantified using the Quantifiler® Duo DNA Quantification Kit. STR profiles were analyzed using the AmpFISTR® Identifiler ® PCR Amplification Kit. The average yield of male DNA obtained after a male grabbed the shirt with dry hands was 1.5 ng and 14 ng for cuttings and M-Vac samples, respectively. Compared to cuttings, this demonstrated a 9.7 fold increase (p = 0.0079) of male DNA when the M-Vac was employed for collection. Another variable explored was the impact sweat may have on the amount of touch DNA deposited. The average yield of male DNA obtained after a male grabbed the shirt with sweaty hands was 4.5 ng and 25 ng for cuttings and M-Vac samples, respectively. Compared to cuttings, a 5.8 fold increase (p = 0.0042) of male DNA was observed when the M-Vac was used for sample collection. In this study, the M-Vac was significantly more effective at obtaining touch DNA than fabric cuttings, thus warranting further investigation. The M-Vac could be useful for recovering touch DNA as evidence in the forensic science field.
M-Vac Forensic DNA Collection System by Lisa Busjahn
The M-Vac System enables investigators to solve more crime through better DNA collection. It opens doors by collecting DNA from porous and rough evidence. It helps detectives and CSI move cases forward. For example, the M-Vac collected probative DNA on a cold case victim’s water soaked clothing.
We all know that even the best DNA processing equipment cannot amplify DNA that is not recovered in the sampling or collection process. The M-Vac® helps by simply collecting more DNA.
What if traditional collection methods have already been used on an item? The M-Vac® is a valuable tool in those scenarios and can often result in conclusive profiles even after traditional methods have been used and yielded inconclusive partials. It gives cases a second chance.
For example, in an independent verification, after swabbing a saliva stain on cotton fabric, the M-Vac® was still able to collect 22X more saliva DNA. This shows that not only does the swab leave a significant amount of DNA material behind, but also that the M-Vac® System is much more capable of collecting DNA material from porous surfaces.
The M-Vac® System is also known as a wet-vacuum sampling device, a vacuum-assisted instrument, a forensics vacuum, a DNA recovery system and other descriptive terms in literature and news articles. The M-Vac®System is also effective in sampling meat or produce for pathogens, checking environments for bacteria contamination and assuring the absence of bio-hazards in bio-defense.
Validations
The M-vac has been extensively tested by M-Vac Systems, universities, law enforcement agencies, labs and other companies. Validations for forensic industry are listed below.
- Washington State Patrol Validation
- Philadelphia PD Research
- DNA Labs Validation
- UC Davis – Skin Research
- UC Davis – Post Shower Research
- UC Davis – Cutting Comparison
- Cedar Crest – Touch on Different Fabrics
- Boston – Swabbing and Tape – Denim
- Boston – Blood and Semen on Denim, Carpet, Tile and Brick
- Filter Verification Testing
Formula Forensic Solutions, L.L.C. is a independent consulting company and distributor for forensic products and training. We are proud to carry the M-Vac Forensic DNA Collection System in our line of offerings.
For more information please contact Lisa Busjahn at ffsbusjahn@gmail.com or call 844-428-7524.
This is a reposting of the original article Lisa posted on LinkedIn. To see that article click here.
mvacblog 