This CLE program offers a technical and practical overview of probabilistic genotyping (PG) software used in modern DNA analysis. Viewers will gain an understanding of how PG systems such as STRmix, TrueAllele, and Lab Retriever are used to interpret complex or mixed DNA samples when traditional methods fall short. The program explains how these algorithms assign statistical weight to potential contributors and produce likelihood ratios—figures that are frequently used in court to suggest the strength of a DNA match.

Elizabeth Vasquez breaks down the key components of PG software, including the assumptions built into the models, variability in outputs based on user-defined parameters, and how different software programs can produce different results from the same input data. Viewers will learn the limitations of these tools, including concerns about transparency, reproducibility, and error rates. The program also outlines areas of potential legal challenge, such as the lack of peer-reviewed validation, closed-source code, and discrepancies in lab implementation and documentation.

Criminal defense attorneys will benefit from specific strategies for interrogating PG-based testimony in court, identifying where software outputs may overstate the strength of the evidence, and using discovery requests to obtain audit trails, input files, and lab notes critical to cross-examination. This training is essential for any attorney litigating cases involving complex DNA mixtures or statistical match claims derived from PG software.