Body Fluid Identification in Samples Collected after Intimate and Social Contact: A Comparison of Two mRNA Profiling...

Area of Science:

• Forensic Science
• Genetics
• Molecular Biology

Background:

• Associating body fluids with individuals in crime scenes is crucial for investigations.
• Current DNA analysis and body fluid detection are independent, limiting direct association.
• Coding region SNPs (cSNPs) in RNA transcripts offer a potential solution for linking body fluids to contributors.

Purpose of the Study:

• To compare Massively Parallel Sequencing (MPS) and Capillary Electrophoresis (CE) for mRNA marker detection.
• To evaluate the efficacy of cSNP genotypes in associating body fluids with their contributors.
• To assess the performance of the BFID-cSNP-6F assay and Ion S5™ System for forensic body fluid analysis.

Main Methods:

• Targeted RNA sequencing of 158 forensic samples (boxershorts, fingernail, penile swabs) from 12 couples.
• Utilized the Ion S5™ System and the BFID-cSNP-6F assay for analysis.
• Compared MPS and CE methods for mRNA marker detection and cSNP genotyping.

Main Results:

• MPS demonstrated a lower success rate than CE in detecting vaginal mucosa.
• cSNP genotyping provided valuable additional information for associating body fluids with contributors.
• Successful association of body fluids with individuals was achieved in most cases using cSNP data.

Conclusions:

• cSNP analysis of RNA transcripts is a promising method for linking body fluids to individuals in forensic casework.
• While MPS has limitations for certain sample types, cSNP genotyping enhances the associative power of body fluid analysis.
• The study highlights the potential of integrating molecular techniques for more comprehensive forensic investigations.