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Evolution and population dynamics of natural transformation in Haemophilus influenzae
Abstract
Genetic mixis, or sexuality, in bacteria is well understood at the molecular level, yet the evolutionary forces ultimately responsible for the origin and maintenance of bacterial sex remain obscure. The extent to which recombination contributes to the evolution of natural bacterial populations is currently a subject of much debate. Bacterial populations are highly diverse at the protein level, yet strains that carry an identical array of protein electromorphs at multiple loci are repeatedly isolated, indicating limited recombination. In contrast, at the DNA level, bacterial genomes appear to be chimeras, with individual regions of the chromosome having different evolutionary histories. In this dissertation, Haemophilus influenzae will be used as a model system for the study of one form of sex in bacteria, natural transformation. First, the DNA repair hypothesis for the evolution of natural transformation is tested experimentally. Then, a mathematical model of the population dynamics of transformation is developed which allows the rate of gene substitution by transformation to be estimated. Finally, the impact of ecological isolation and recombination on the genetic structure of bacterial populations is investigated using a computer simulated model of the evolution of multilocus electrophoretic genotypes in subdivided populations experiencing recurrent periodic selection and recombination between subpopulations.
Subject Area
Genetics|Zoology
Recommended Citation
Mongold, Judith Anne, "Evolution and population dynamics of natural transformation in Haemophilus influenzae" (1992). Doctoral Dissertations Available from Proquest. AAI9305870.
https://scholarworks.umass.edu/dissertations/AAI9305870