An emergent mechanism for speciation in microbes: theory and comparative genomics

Kalin Vetsigian and Nigel Goldenfeld, Physics, UIUC

We show that strongly-interacting communities of microbes exhibit a non-trivial phase diagram that depends upon the details of homologous recombination and the competition with point mutation. Possible phases include one that is genetically uniform, and another that is biodiverse. A comparative genomic study of sequenced, closely-related microbial genomes finds evidence for the predicted signature of this phase transition in Bacillus. Our work highlights the important role that emergent, collective effects can play in determining microbial community structure and speciation. Work supported by the National Science Foundation.