Developmental Validation of the Microreader 23HS Plex ID System: A Novel Supplementary Non-CODIS STR Multiplex Assay...

Area of Science:

• Forensic Genetics
• Molecular Biology
• Human Identification

Background:

• Short tandem repeat (STR) analysis is crucial for human identification in forensics.
• Existing CODIS (Combined DNA Index System) loci may not always be sufficient for complex cases.
• Development of supplementary STR assays enhances discriminatory power.

Purpose of the Study:

• To develop and validate a novel supplementary STR multiplex assay, the Microreader 23HS Plex ID System.
• To enable simultaneous profiling of 23 non-CODIS and 3 CODIS STR loci plus amelogenin.
• To assess the assay's performance according to international and Chinese validation standards.

Main Methods:

• Development of the Microreader 23HS Plex ID System targeting 26 loci.
• Comprehensive validation including PCR conditions, sensitivity, precision, accuracy, reproducibility, and inhibition testing.
• Mixture and population studies involving 500 individuals of Han ethnicity.

Main Results:

• The Microreader 23HS Plex ID System demonstrated reliability, robustness, and well-balanced peak heights.
• Assay sensitivity was 0.125 ng of template DNA, with detection of minor alleles in various mixture ratios.
• Population data yielded a cumulative random match probability of 7.757 × 10⁻²⁷ and high power of discrimination.

Conclusions:

• The Microreader 23HS Plex ID System is a validated and robust assay for forensic use.
• It serves as a valuable supplementary tool, particularly for complex kinship testing and challenging STR mutation cases.
• The system significantly enhances forensic DNA profiling capabilities beyond standard CODIS loci.