Modelling PowerPlex® Y stutter and artefacts.

Area of Science:

• Forensic genetics
• Molecular biology
• Population genetics

Background:

• Autosomal short tandem repeat (STR) analysis is a cornerstone of forensic DNA profiling.
• Stutter, an artifact in STR analysis, can complicate allele interpretation and requires accurate modeling.
• Y-STR markers offer unique advantages for male lineage tracing but require specific analytical considerations.

Purpose of the Study:

• To evaluate the applicability of existing autosomal STR stutter models to Y-STR markers.
• To develop and propose new models for predicting stutter ratios and artifact heights in Y-STR loci.
• To enhance DNA interpretation using an expert system with continuous data analysis.

Main Methods:

• Investigated suitability of autosomal STR stutter prediction models for Y-STR markers.
• Developed models for back stutter, double back stutter, and forward stutter ratios for PowerPlex® Y multiplex loci.
• Analyzed stutter-like artifact heights at DYS19 and DYS385, using longest uninterrupted stretch of repeats (LUS), marker, and parent allele height as explanatory variables.

Main Results:

• Proposed models for predicting expected stutter ratios and artifact heights for Y-STR loci.
• Identified LUS, marker, and parent allele height as significant factors influencing stutter.
• Demonstrated the potential for integrating these models into expert systems for continuous DNA interpretation.

Conclusions:

• Existing autosomal STR stutter models can be adapted for Y-STR analysis, with modifications.
• The proposed Y-STR stutter models improve the accuracy of predicting stutter ratios and artifact heights.
• These models are crucial for advancing automated and continuous DNA interpretation methodologies in forensic science.