Forensic blood evidence analysis using RNA targets and novel molecular tools

Abstract

In the realm of forensic investigation, messenger RNA (mRNA) is a good source for specimen analysis, owing to tissue-specific expression patterns for many transcripts. Thus, differentiation of bodily fluids collected at a crime scene is possible if the proper target mRNA is identifiable and detectable using molecular methods. With the analysis of menstrual blood evidence, for example, the matrix metalloproteinase (MMP) family of genes encodes proteins involved in extracellular matrix breakdown during tissue remodeling, and in particular MMP11 and MMP7 mRNA have proven useful for forensic blood evidence analysis. Nucleic acid sequence based amplification (NASBA) is a highly sensitive RNA transcription-based amplification method used to detect gene expression. As an emerging real-time technology, NASBA holds promise as a tool to rapidly and sensitively amplify mRNA markers associated with the MMP genes to verify the presence of menstrual blood in a forensic sample, and has a number of advantages compared to reverse transcriptase polymerase chain reaction. The purpose of this review is to overview the current state of mRNA analysis in forensic evidence casework and to highlight areas of research, progress, and development in the near-term future that will lead to reduction of case evidence backlog in crime laboratories in developed countries.

Differential genes expression biomarkers for menstrual and peripheral blood stains analysis

“…MMP7 is thought to be more relevant as a marker for mRNA amplification because it can be amplified by the use of easily acquired commercially produced testing kits for immediate use in a forensic laboratory. MMP7 has smaller amplicon size (101 base pairs bp) in comparison to MMP11 (455 bp) that makes MMP11 a less valuable marker for menstrual blood identification in a forensic laboratory (Counsil and McKillip, 2010). Moreover, despite the successful reduction of MMP11 amplicon size down to 200 bp in some studies it is still much larger than mRNA amplified from the MMP7 menstrual blood marker (Ferri et al, 2004).…”

Application of Ribonucleic Acid (RNA) in Forensic Sciences

“…The purpose of these tests is to narrow down the range of suspects or victims associated with a crime that is under investigation. 40 But there are certain demerits of these methods like consumption of sample, laborintensive, time consuming, non-specific, and technologically diverse. To eliminate all such problems, there is a need for molecular-based identification of these fluids.…”

“…Blood is the most prevalent evidence of violent crime scenes such as homicide and sexual assault. 40 It becomes a dire need to identify blood as body fluid and source of the blood. The identification of the source of the blood gains prime importance in certain scenarios like sexual assaults.…”

“…44 The other method for menstrual blood detectionis based on differences in isozyme patterns, fibrinolytic activity, hormone concentrations, and fibrin fibrinogen degradation products. 40 Haas et al 22 produced 'highly sensitive duplex' (HBB, HBA) and 'moderate sensitivity' pentaplex (ALAS2, CD3G, ANK1, PBGD, and SPTB). 22 Kohlmeier and Schneider 8 obtained successfully an RNA profile for two specific blood markers HBB, SPTB from 23-year blood stains from different career materials jeans, leather, wood, wallpaper, carpet, wool, and nylon fabric.…”

“…The RT-PCR allows the detection of relative gene expression levels in different samples. 40 Quantitative reverse transcription PCR (qRT-PCR) is very sensitive and specific as compared to the other two precedent approaches and can be used for absolute quantification. In forensic cases, the quantity of genetic material collected can be less, and therefore, it is important to use a methodology that requires a fairly low amount of RNA.…”