title: The influence of swabbing solutions on DNA recovery from touch samples.
abstract: There has been minimal research into how to best obtain DNA from touch samples. Many forensic laboratories simply moisten a swab with water and use it for collecting cells/DNA from evidentiary samples. However, this and other methods have not been objectively studied in order to maximize DNA yields. In this study, fingerprints were collected using swabs moistened with water or laboratory or commercially available detergents, including sodium dodecyl sulfate (SDS), Triton X-100, Tween 20, Formula 409(®) , and Simple Green(®) . Prints were swabbed, DNA isolated using an organic extraction, yields quantified, and relative yields compared. In all cases, the detergent-based swabbing solutions outperformed water, with SDS and Triton X-100 producing significant increases in yield. Short tandem repeat profiles were consistent with the individuals that placed them. Subsequent analysis of SDS concentrations for collecting touch DNA demonstrated an increase in DNA yield with increasing SDS concentration, with an optimal concentration of approximately 2%.
authors.affiliation: Forensic Science Program, School of Criminal Justice, Michigan State University, East Lansing, MI, 48824.
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Thomasma
authors.forename: David R
authors.initials: DR
authors.lastname: Foran
mesh_terms: D004247:DNA / Q000302:isolation & purification*; D016172:DNA Fingerprinting; D003878:Dermatoglyphics; D003902:Detergents; D006801:Humans; D018895:Microsatellite Repeats; D060888:Real-Time Polymerase Chain Reaction; D012967:Sodium Dodecyl Sulfate; D013048:Specimen Handling / Q000379:methods*; D014110:Touch
chemical_list: D003902:Detergents; D012967:Sodium Dodecyl Sulfate; D004247:DNA
keywords: DNA typing/collection; double swabbing; forensic science; low copy number DNA; quantifiler; short tandem repeats; sodium dodecyl sulfate (SDS); touch DNA