Microbial forensic investigations in the context of bacterial population genetics

Population genetic data provide the foundation for making “DNA fingerprinting” relevant to forensic analysis. Different genotypic methods/marker systems provide greater or lesser discrimination power, but even high-resolution methods may be of limited use without relevant population genetic databases and valid approaches for interpretation. A reiterative schema is provided for the application of genetics to microbial forensic analysis. It involves the formulation of attribution hypotheses and suggested confidence estimation methodologies. Alternative hypotheses should be quantitatively tested for their comparative strengths and assigned relative probability values and likelihood ratios. The replication mode for each pathogen is critical for choosing analysis methods. Caution is given in that a lack of biological understanding of a pathogen could lead to false assumptions and erroneous conclusions.