Novel messenger RNAs for body fluid identification

Area of Science:

• Forensic science
• Molecular biology
• Genetics

Background:

• Accurate identification of biological evidence source (body fluid, cell type) is critical in forensic investigations.
• Messenger RNA (mRNA) profiling is a sensitive tool for body fluid identification, complementing DNA analysis.
• Current mRNA profiling is limited by a small number of known markers, risking misinterpretation due to cross-reactions.

Purpose of the Study:

• To characterize six novel messenger RNA (mRNA) markers for improved body fluid identification in forensic samples.
• To evaluate the specificity and sensitivity of these novel mRNA markers compared to existing ones.

Main Methods:

• RNA-sequencing (RNA-Seq) was used to identify potential novel mRNA markers.
• Six novel mRNA candidates (HBD, SLC4A1, TNP1, KLK2, MMP3, STC1) were characterized.
• Expression profiles were evaluated using singleplex endpoint reverse transcription polymerase chain reaction (RT-PCR).

Main Results:

• HBD and SLC4A1 showed specificity for circulatory blood; KLK2 was specific for seminal fluid.
• TNP1 (spermatozoa), MMP3, and STC1 (menstrual fluid) exhibited minor, non-reproducible cross-reactions with non-target samples.
• All novel mRNA candidates demonstrated higher sensitivity than established markers, particularly for menstrual fluid detection.

Conclusions:

• The six novel mRNA markers supplement existing markers for enhanced body fluid profiling.
• These markers improve the sensitivity and reliability of identifying blood, semen, and menstrual fluid in forensic contexts.
• The characterized mRNAs represent promising targets for advancing forensic biological evidence analysis.