Crime scene DNA sampling by wet-vacuum applying M-VAC: -
2015 (English)In: Abstracts ISFG, 2015, 317- p.Conference paper, Abstract (Refereed)
Swabs provide efficient sampling of crime scene stains from surfaces and items for subsequent forensic DNA analysis. However, swabs are not optimal for large dilute stains or absorbing materials such as fabrics. Tape-lifting works well for fabrics, but is not ideal for dried stains. A possible sampling alternative is the M-Vac wet-vacuum instrument (M-Vac Systems Inc.). We have evaluated the M-Vac for sampling of dried stains on inert surfaces and fabrics. M-Vac gave significantly higher DNA concentrations from dried saliva stains on laminated wood, compared with cotton swabs (mean DNA concentrations 1.14 and 0.57 ng/Î¼L, respectively, p=0.02). On glass, M-Vac and cotton swabs gave similar DNA concentrations. Additionally, M-Vac retrieved over twice as much DNA from saliva stains on cotton fabric (T-shirt) compared with towels (terry-cloth), showing that the absorption properties of the surface affect wet-vacuum sampling. M-Vac was also applied for retrieving wearer DNA from clothes, enabling generation of complete DNA profiles from denim jeans, leggings and cotton T-shirt. Partial DNA profiles were retrieved from an â€œoffenderâ€ pressing his hand against the shoulder of a person wearing a T-shirt. There, the major parts of the resulting mixed DNA profiles were from the wearer/â€victimâ€, indicating that M-Vac may not be ideal for sampling of touch DNA from clothes. Wet-vacuum sampling requires a fairly large instrument, trained users and DNA extraction procedures handling large sample volumes. Still, in especially important cases, wet-vacuum could enable sampling of large dried stains that may be difficult to sample with other procedures.
Place, publisher, year, edition, pages
2015. 317- p.
IdentifiersURN: urn:nbn:se:liu:diva-120900OAI: oai:DiVA.org:liu-120900DiVA: diva2:849423
26th Congress of the International Society for Forensic Genetics