Ars Technica reports on research out of Cal Tech where scientists were able to create logic gates out of RNA molecules. Thus far, they've demonstrated AND gates and OR gates, with work proceeding on more complicated systems. The work shows promise for ability to easily detect the presence of particular chemicals. The abstract from the scientists' paper is available at Science. Quoting Ars: "Detecting tetracycline isn't especially interesting, but RNA that binds to specific small molecules is actually relatively easy to make; repeated rounds of amplification and selection for binding can evolve these RNAs in a couple of days. This means that, in a matter of days, researchers can grow yeast colonies that glow in response to a variety of chemicals, or even to combinations of chemicals. More complicated circuits should be possible if the ribozymes are inserted into messenger RNAs that encode transcription factors, which could, in turn, regulate genes that encode yet other ribozymes."