DISSERTATION RESEARCH: Evaluating frequency-dependent selection on Borrelia burgdorferi

Yale University, New Haven CT

Investigators

Abstract

Understanding how pathogen diversity is maintained is the central question of this project. It has been suggested that two mechanisms of natural selection may maintain genetic diversity within the bacterium Borrelia burgdorferi: frequency-dependence and host specialization. Computer simulation modeling, field data collection, and molecular techniques will be integrated to evaluate the evidence for these mechanisms of selection. The first aim of this project is to develop a method for identifying different genotypes of B. burgdorferi from a large number of samples. This method will then be used to monitor wildlife populations naturally infected with this pathogen, for evidence of either selection mechanism. B. burgdorferi is the bacterium that causes Lyme disease, which has a significant public health impact in the United States. Diversity within this species also relates to human illness, as some types tend to cause more severe disease than others. Understanding how this diversity is maintained may provide insight into the evolution of virulence in this bacterium. The molecular identification method to be developed should be an economical and effective tool for further studies on this pathogen and system. Findings will be disseminated to high school students and the general public, via established relationships between the co-PI and various educators and public outreach programs.