Katherine Unger in Science:
DNA may be the blueprint for life, but for many bacteria it’s also decent food in a pinch. Now, researchers have identified genes that allow Escherichia coli and many other types of bacteria to eat DNA when other nutrients aren’t readily available.
DNA from dead cells and organisms floats around in the environment, and some bacteria can usher it inside their cell walls. Scientists believe microbes use the DNA to diversify their genetic material, or perhaps to repair it. But there’s a third possibility: In 2001, bacteriologist Steven Finkel of the University of Southern California (USC) in Los Angeles and a colleague showed that E. coli could survive even when DNA was its only source of nutrition. That was puzzling because most researchers thought E. coli was incapable of taking up extracellular DNA to incorporate into its own genome. But now Finkel and Vyacheslav Palchevskiy, also of USC, have found genes that apparently allow E. coli to consume the stuff.