Increased amplification success from forensic samples with locked nucleic acids.

Area of Science:

• Forensic Science
• Molecular Biology
• Genetics

Background:

• Forensic DNA profiling success is often limited by inadequate sample quantity and quality.
• Standard PCR protocols may struggle with inhibited or low-quantity forensic samples.
• Locked nucleic acids (LNAs) have shown promise in enhancing PCR amplification in other applications.

Purpose of the Study:

• To evaluate the efficacy of LNA-modified PCR primers for forensic DNA analysis.
• To determine if LNAs improve amplification success rates for challenging forensic samples.

Main Methods:

• Redesigned PCR primers for four common STR loci to incorporate LNA bases.
• Compared amplification success of LNA primers against standard DNA primers using buccal and simulated forensic samples.
• Assessed performance in both singleplex and multiplex PCR reactions.

Main Results:

• LNA primers demonstrated significantly higher amplification success rates compared to standard primers.
• Peak heights increased up to 5.75× in singleplex amplifications with LNA primers.
• LNA primers outperformed standard primers in multiplex reactions, offering easier optimization and improved success.

Conclusions:

• Incorporating LNAs into PCR primers is a viable strategy to enhance forensic DNA profiling.
• LNA primers can overcome limitations posed by challenging forensic samples, increasing profiling success.
• This approach offers a valuable tool for improving DNA analysis in forensic casework.