OXYGEN'S GIFT: Without O, life would be a lot simpler

A GRAND PLOT POINT IN THE history of life was the center-stage entry of oxygen into the atmosphere roughly 2.2 billion years ago. At the time, oxygen was a waste gas that emanated from the bacterial innovators of photosynthesis and posed mortal hazards to the anaerobic life that had been evolving for more than a billion years. With oxygen's arrival, the choices for the planet's microbial masses were to die, hide from oxygen, or evolve ways to live with it. Using a bioinformatics approach involving data from the genomes of 70 of today's aerobic and anaerobic microbes, as well as thousands of enzymatic reactions, Jason Raymond of Lawrence Livermore National Laboratory and Daniel Segre of both LLNL and Boston University have attempted to infer "how oxygen availability changed the architecture of metabolic networks" ( Science 2006 , 311 , 1764). It's the type of insight that researchers can use to reconstruct how early microbial life evolved into complex ...