Towards an Understanding of the Population Genetics of Plant-Colonizing Bacteria

Abstract

Publisher Summary This chapter discusses the population genetics of plant–colonizing bacteria. Population genetics is the study of evolutionary change and it is concerned with natural genetic diversity, its causes, its distribution, and its biological significance. More specifically, population genetics is concerned with the basic forces of evolution, that is, mutation, recombination, migration, natural selection and genetic drift, and the contribution that these forces make to the nature and rate of evolutionary change. The link between the effects of specific evolutionary forces and patterns of variation is provided by the theory of population genetics, which gives evolutionary biology it's most significant and far–reaching body of theory. A variety of methods are used for detecting genetic variation in populations and include traditional markers such as specific virulence genes, morphological markers, electrophoretic markers, polymerase chain reaction, and direct DNA sequence analysis. The appropriateness of each method depends largely on the nature and scope of the questions being addressed. Populations of strictly asexually reproducing organisms are, by definition, clonal. In such populations differences between individuals arise due to spontaneous mutation. The chapter introduces bacterial population genetics and provokes microbial ecologists and phytopathologists to consider questions relating to the extent and significance of genetic variation within plant–colonizing bacterial populations.