Cyanobacteria are a key species in Earth's history, as they introduced atmospheric oxygen for the first time. The analysis of their evolution therefore provides important insights into the formation of modern aerobic ecosystems. For a long time, a certain type of fossil lipid, so-called 2-methylhopanes, was considered to be an important biomarker for Cyanobacteria in sediments, some of which are hundreds of millions of years old. However, this came into doubt when it turned out that not only Cyanobacteria but also Alphaproteobacteria are genetically capable of producing these lipids. from Latest Science News -- ScienceDaily https://ift.tt/3KB0qNn