A Time to Scatter Genes and a Time to Gather Them: Evolution of Photosynthesis Genes in Bacteria

Abstract

Genome sequencing opened entirely new avenues for studying the evolution of photosynthesis. By systematically comparing sequences of photosynthesis-related genes and their products in phototrophic members of diverse bacterial lineages, it has become possible to delineate their common and distinct traits, analyse their evolutionary relationships, and reconstruct the likely scenarios for the overall evolution of the photosynthetic machinery. We consider here the comparative genomics data on the distribution of photosynthesis genes among certain representatives of six bacterial phyla, Acidobacteria, Chlorobi, Chloroflexi, Cyanobacteria, Firmicutes, and Proteobacteria and put these data in a broader geochemical context. We address the tentative nature of the first photosynthetic organisms, the driving forces behind their origin, and review the evidence for the early origin of abiogenic photosynthesis.