A study of 41 genomes from uncultured microorganisms provides new information about the evolution of aerobic respiration in Cyanobacteria. Photosynthetic Cyanobacteria are thought to have changed the course of life’s evolution on Earth by playing an important role in the oxygenation of Earth’s atmosphere roughly 2.3 billion years ago. By examining the genomes of multiple Cyanobacteria, as well as other related bacterial lineages, researchers found evidence that photosynthesis likely evolved in Cyanobacteria multiple times. In addition, modern photosynthesis could have arisen from the fusion of two different photosynthetic systems via lateral gene transfer. The work provides important details about how and when cyanobacteria evolved to release oxygen via photosynthesis.

The paper, “On the origins of oxygenic photosynthesis and aerobic respiration in Cyanobacteria,” was published in the journal Science. The work was supported in part by NASA Astrobiology through the Exobiology & Evolutionary Biology Program.