Methods for obtaining STR???quality touch DNA from archived fingerprints

As submitted by the proposer: Latent fingerprints are common sources of touch DNA found at crime scenes. Customary collection methods involve dusting, tape-lifting, and attaching the fingerprint to a paper backing card for storage, which sandwiches the DNA between adhesive and paper surfaces. Many older case files contain fingerprints acquired by the tape-lifting and backing method mentioned above, most of which have never been tested for DNA. For these types of samples, there is limited reported success as well as minimal available research on best methods for DNA processing of archived fingerprints. It is well accepted that detection of the source of the fingerprint may depend on shedder status of the individual leaving the print. Further, in many cases, it is uncommon to even collect fingerprints from paper substrates after on-scene enhancement and photography. Lastly, it is well known that outdated methods for collecting latent prints often did not include the use of gloves or other personal protective equipment and that fingerprint brushes are/were often used for multiple collections without cleaning. In this proposal we seek to determine if it is possible to obtain sufficient high-quality DNA for successful STR amplification from archived tape-lifted, paper-backed latent fingerprints. Additionally, we seek to determine the best practices for both collecting fingerprints in this manner, on scene, as well as downstream laboratory practices. Specifically, we plan to examine the effect of prints from several non-porous and porous substrates using standard enhancement powders. This will be followed by an evaluation of DNA extraction methods and lysis approaches (cuttings versus swabbing with a variety of diluents). Further, we will examine the effects of archival time on STR success, and the effects of brush reuse for collection of latent fingerprints. Lastly, source attribution will be investigated to determine if a link can definitely be established between the DNA profile obtained and the source of the fingerprint; mixtures will be documented and percentage of minor contributor alleles will be noted. Once best practices have been clearly delineated, additional studies using low-template DNA testing techniques will be explored in an effort to improve analysis results. ca/ncf