The origin and evolution of cyanobacteria

Abstract

The review considers problems of evolution of cyanobacteria, including geobiological aspects of the origin of these prokaryotes, the appearance of oxygenic photosynthesis, multicellularity, and diazotrophy, from the standpoint of comparative phylogenomics. Special attention is paid to the contribution of different genetic processes (mutations, genome rearrangements, genome reduction, horizontal gene transfer) to the evolution of cyanobacterial genomes. The patterns of genetic variability associated with (a) the level of gene polymorphism, (b) the expansion of gene families, and (c) genomic rearrangements mediated by mobile elements are summarized. Based on the data of genomic phylogeny, a modified scheme of a possible sequence of evolutionary stages in the main taxonomic groups of cyanobacteria was constructed on the scale of the geological history of the Earth.