A team of researchers from Virginia Tech and the University of California, Berkeley, found that a protein that activates photosynthesis in plants is older than oxygen. They think it likely developed from ancient microbes 2.5 billion years ago. The research team came to this conclusion by looking at the microbes known as Achaea that form methane. They live in areas that are absent of oxygen. They think that since methanogens developed before oxygen appeared on earth, that possibly the protein thioredoxin—which plays a major role in contemporary photosynthesis—managed anaerobic life. They say studying methanogens is important because they play a key role in the carbon cycle and are important to human health as well as climate change.