Studies of diversification at the level of populations of bacteria in the genus Bacillus are proposed. These analyses will differentiate among alternative models for population genetic structure, models of evolution, and the genetic and phenotypic distinctness of bacterial species in the genus. The central focus is on the evolutionary interplay of clonality and genetic recombination via exchange of genes among cells, clones and species in Bacillus. The question of how cosmopolitan the species are, i.e., the same everywhere genetically and phenotypically, is also a key aspect of the research. Are the species truly global? A great advantage of the proposed research is that direct experimentation with genetic exchange between populations is possible. The studies will involve Bacillus from three ecologically divergent geographical areas: Sonoran Desert, high-altitude Rocky Mountains, and tropical lowland rainforest. Such investigations will inform us about the processes and consequences of evolution in a group of bacteria which have populated the earth since the surface soils and waters became oxygenated about 2 billion years ago, and about evolutionary mechanisms which continue at present among these organisms in both altered and unaltered environments.
