Molecular evolution of sensory domains in cyanobacterial chemoreceptors.

Components of the chemotaxis system encoded in multiple homologous operons were identified in five cyanobacterial genomes. Analysis of phylogenetic profiles, genomic context, domain architectures and sequence identity reveal that sensory modules of chemoreceptors that detect environmental cues are the subject of frequent domain birth and death events and have accelerated rates of sequence evolution. This fact could explain a remarkable diversity of the sensing repertoire of chemotaxis receptors in microorganisms.