For robot builders hoping to one day achieve a robot with a complexity equivalent to a single-celled animal, the bar has just been raised. A National Science Foundation news release describes new research into how biological cells store information about a cell's state and operation using biochemical switches. Naren Ramakrishnan, a professor of computer science at Virginia Tech, and Upinder S. Bhalla at the National Centre for Biological Sciences in India tried a new approach by looking at cells from the standpoint of an electrical engineer. Using a supercomputer, the researchers located thousands of chemical reactions that form bistable circuits capable of storing binary information. They also discovered the switches are related to each other, with more advanced switches identical to simpler switches but with one or two additional chemical reactions, suggesting possible clues to their evolutionary development within the cell (the diagram above shows how the newly discovered switches are related). The switches also form the equivalent of an electronic circuit. The next step is to look for other functional units such as oscillator and amplifiers, until it's possible to understand a complete "wiring diagram" of cells. To read all the technical details of the research, see the paper Memory Switches in Chemical Reaction Space (PDF format).