Forensically relevant anatomical brain regions cannot be sub-differentiated by RNA expression analysis

Area of Science:

• Forensic science
• Molecular biology
• Neuroscience

Background:

• Biological traces from head injuries can aid criminal investigations.
• Differentiating specific brain regions from forensic samples is crucial for accurate analysis.

Purpose of the Study:

• To identify and validate messenger RNA (mRNA) candidates for sub-differentiating forensically relevant brain regions.
• To assess the feasibility of RNA expression analysis for forensic applications.

Main Methods:

• Massively parallel sequencing of whole transcriptomes from frontal, temporal, parietal, and occipital lobes.
• Bioinformatical analysis, classification, and biostatistical selection of mRNA candidates.
• Validation using Multiplex-RT-PCR and capillary electrophoresis.

Main Results:

• Minimal relative mRNA upregulation was observed, primarily in the parietal lobe.
• Two candidates (PVALB, CDR2L) showed upregulation in the cerebellum; PVALB was not reliably detected, while CDR2L was present in all lobes.
• Differences in mRNA expression across the four cerebral cortex regions were not pronounced enough for forensic application.

Conclusions:

• Sub-differentiation of cerebral cortex regions using RNA expression analysis is generally not feasible for forensic purposes.
• The subtle mRNA expression variations limit the utility of this approach in forensic investigations.