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Methods for Obtaining STR-Quality Touch DNA from Archived Fingerprints

NCJ Number
Date Published
March 2017
23 pages
This is the final summary report on a project that evaluated analytical procedures for the processing of archived, paper-backed, latent fingerprint lifts, so as to make recommendations to crime scene, criminal justice, and forensic DNA practitioners on processing archived prints in the laboratory.

The project provides evidence that should encourage forensic laboratories and investigators to consider doing DNA analysis from archived latent fingerprints, particularly when they are the only potential source of physical or biological evidence available. Viable DNA was found to be available in some archived latent fingerprint samples, as well as in the surface area left behind after swabbing, and it can be retrieved for DNA profiling. The findings indicate that when processing archived latent fingerprints for DNA analysis, disassembly of the fingerprint "sandwich" and making direct cuttings of the latent print area results in more template DNA available for downstream amplification and improved STR profiles compared with commonly used swabbing methods; however, the research also indicates that the double-swabbing method can be a reliable method and may perform best when the initial swab is pre-wet with a diluent that includes a lysis buffer and protein-degrading enzyme. In addition, the use of a silica-based column extraction method that has been optimized for use with forensic/challenged samples, followed by a gel-column concentration method, may increase the chances of obtaining informative STR profiles when used instead of other common methods/combinations. On the other hand, the research indicated that the addition of a post-amplification purification step did not improve the STR profiles obtained from these samples. The increased sensitivity is more likely to increase the presence of artifacts that complicate data interpretation. Materials and methods are described. 50 references

Date Published: March 1, 2017