Development of a fast, simple profiling method for sample screening using high resolution melting (HRM) of STRs

Area of Science:

• Forensic Science
• Molecular Biology
• Genetics

Background:

• Traditional short tandem repeat (STR) profiling is time-consuming and costly for large numbers of forensic samples.
• A need exists for efficient preliminary screening methods to prioritize samples for definitive analysis.

Purpose of the Study:

• To develop and validate a high-resolution melting (HRM) assay for the preliminary individualization of forensic DNA samples.
• To reduce the cost and time associated with extensive STR profiling of nonprobative samples.

Main Methods:

• Developed a real-time PCR-based HRM assay targeting three forensic short tandem repeat (STR) loci: vWA, D18S51, and THO1.
• Optimized assay parameters including Mg++ concentration, annealing/extension conditions, and reagent volumes.
• Validated the assay for reproducibility, genotype uniformity, melting profile consistency, inhibitor tolerance, and mixture analysis.

Main Results:

• The HRM assay successfully detected length and sequence variations in the selected STRs, enabling preliminary sample differentiation.
• The assay demonstrated reproducibility and consistency across various conditions, including the presence of inhibitors and sample mixtures.
• The assay can also be used for DNA quantification when run with a standard curve.

Conclusions:

• The developed HRM assay provides a cost-effective and time-efficient method for preliminary screening of forensic DNA samples.
• This approach can significantly streamline the forensic analysis workflow, particularly for cases with numerous samples or suspects.
• HRM offers a valuable tool for prioritizing samples for subsequent, more detailed STR profiling.