An anonymous reader writes "
"For 11 years, Jill Banfield at the University of California, Berkeley, has collected and studied the microbes that slime the floors of mines and convert iron to acid, a common source of stream pollution around the world. Imagine her surprise, then, when research scientist Brett Baker discovered three new microbes living amidst the bacteria she thought she knew well. All three were so small — the size of large viruses — as to be virtually invisible under a microscope, and belonged to a totally new phylum of Archaea, microorganisms that have been around for billions of years. What made Baker's find possible was shotgun sequencing, a technique developed... to sequence the human genome in record time."