Population Genetic Considerations in Statistical Interpretation of Microbial Forensic Data in Comparison with Human DNA Forensic Standard

This chapter focuses on some of the considerations that need to be employed to build a statistical paradigm for interpreting microbial forensic data. There are many differences in the genetic characteristics of microorganisms and these will determine to what extent a statistical paradigm can be put in place for interpretation of microbial forensic data. In microbial forensics, one may consider attribution solely to be the "fingerprinting" of a pathogenic agent. However, because of the clonal nature of many microorganisms and, on a case-by-case basis, lack of population and phylogenetic data, unique identification of a microorganism may rarely be possible. More importantly, the ultimate goal of attribution is identification of persons who committed the bioterrorist act or biocrime, intentionally or inadvertently. Therefore, and most likely, in addition to microbiological analytical tools, traditional forensic analyses, such as human DNA analysis, dermatoglyphic patterns, analytical chemistry, tool marks, computer data, and other techniques will be used to analyze a bioterrorist event or biocrime evidence. Epidemiological data from various documents may also be a valuable set of information to infer the chronological times of transfer of strains between laboratories that are likely contenders of being the nearest genetic neighbor of the evidentiary samples.