Direct amplification of biological evidence and DVI samples using the Qiagen Investigator 24plex GO! Kit

Abstract

Omitting DNA extraction and quantitation can save valuable time in criminal investigations and disaster victim identification (DVI) efforts. In this study, we applied different collection methods and a combination of direct amplification and lysis to various sample types in combination with the Qiagen Investigator 24plex GO! Kit. This “megaplex” kit was designed for direct PCR of DNA references, and validated with Investigator STRGO! lysis buffer. Preliminary experiments resulted in different approaches for each sample type. Missing person reference and/or post-mortem samples like hair roots, toothbrush bristles, muscle tissue and bone shavings could be successfully typed after a Proteinase K lysis step with 2mL of the volume as PCR input. Blood and saliva stains, touched fabrics and fingerprints on glass were tested with direct PCR after collection using tape lifts, cuttings, and various swab types. Using COPAN microFLOQ swabs is the most convenient collection method, but other methods, like tape lifts and small swab cuttings work as well.The two quality standards incorporated in the Qiagen 24plex kits are helpful for trouble shooting. This is especially important in the absence of Q-PCR data. Several samples, e.g. paper tissue cuttings and surface swabs from fingerprints, eye glasses and razors showed inhibition. The PCR may have been affected by the loss of reaction volume through absorption by the swab. Sources of inhibitors could have been the swab or tissue substrate, or the items, e.g. make-up on eye glasses.