This study explored the use of combined DNA typing and protein identification for unfired brass cartridges.
In this study, touched unfired brass cartridges were sampled using dry tape or wet swabs and analyzed by separating DNA and protein from the same collected material, thus producing both genomic and proteomic information. The researchers conclude that proteins can be collected from fingerprints at levels necessary to provide identifying information, thus expanding information obtained from challenging evidence. DNA recovery was similar for both collection methods, with tape yielding an average of 1.36 ± 1.87 ng and swabs, 1.34 ± 3.04 ng. Analysis by mass spectrometry identified 95 proteins, with the two collection methods showing no significant difference (p = 0.76) in the average number of collected proteins: 44.5 ± 10.9, (tape) versus 47.9 ± 20.4 (swabs). Biological evidence analysis from contact traces is adversely affected by low quantity and quality of DNA. Proteins in these samples contain potentially individualizing information and may be particularly important for difficult surfaces such as brass, where DNA may yield incomplete profiles. (Published Abstract Provided)