Identification and Resolution of Capability Gaps in Forensic Science

Although forensic biology is a powerful tool in criminal investigations, there are a number of capability gaps; namely, the interpretation of low-level DNA mixtures, associating the DNA profile with a body fluid, and the issue of consent in sexual offences. A research strategy was developed that utilises whole genome amplification (WGA), messenger RNA and microRNA analysis, DNA profiling, and clothing damage analysis. An evaluation of a WGA technique – multiple displacement amplification - with and without a macromolecular crowding agent, indicated that this may be of use for DNA samples containing certain mixing ratios; however, for this to be truly of use, knowledge of the nature of the sample preanalysis is required, which is not feasible in a forensic environment. A SYBR Greenbased mRNA gene expression test was developed that was capable of distinguishing between saliva and blood by using relative quantitation on real-time PCR. However, the low specificity of the SYBR Green meant that a higher number of controls were required for this to work at forensic standard. A single channel simultaneous analytical test for DNA and microRNA was also developed, which meant that it could be possible to definitively identify the body fluid origin of a DNA profile. This represented a significant step forward in improving forensic biology capability. Reconstruction studies were carried out in response to a sexual assault case where consent was an issue. This study demonstrated that it was possible to cause significant damage to a bra without causing damage to the hook and eye fastening; thus, negating a hypothesis offered by the defence. A long term research strategy has been developed and significant progress has been made in improving the capability of the operational forensic biologist.