| Humans and animals host a myriad of microbes including enteric bacteria of the family Enterobacteriaceae. While these organisms are related, they represent a range of evolutionary strategies and interactions with the host gastrointestinal tract. Clinically important enteric species, including Salmonella enterica and Escherichia coli , have been thoroughly characterized by phenotypic, genetic, and epidemiologic methods. Accordingly, these organisms serve as models for studying the genetic and phenotypic diversity of this bacterial family. Although a few strains have been well characterized, less information is available about the natural history of these organisms and, specifically, how populations experience and adapt to selective evolutionary pressures. The goal of this research is to present a novel perspective on this topic through population genetic analyses. These methods, when applied to longitudinal samples of strains, quantify the abundance and distribution of alleles, genotypes, and phylogenetic groups in evolving populations. The results of each individual research area add to the current understanding of microbial ecology and evolution by incorporating information about populations from natural (biotic and abiotic) sources. |
