pick fights with other strands, one thing that they can't do yet is play computer games -- that is, until now. In what appears to be an early proof-of-concept for DNA computing, scientists at Columbia University and the University of New Mexico have created a basic computer, called the MAYA-II, which has a molecular array of YES and AND logic gates made up of 100 DNA circuits. This allows the MAYA-II to play a complete game of Tic-Tac-Toe against a human opponent, and apparently nearly always win. However, this isn't exactly a fair test, given that the MAYA-II always goes first, and always opens with the center square. Still, even though each move takes 30 minutes to complete, the lead researcher on the project, Dr. Joanna Macdonald of Columbia, says that a DNA computer would be perfect for injection into human subjects to combat disease, because in theory, it would be able to "diagnose and kill cancerous cells or monitor and treat diabetes by dispensing insulin when needed." Useful applications aside, we're ready to take on the MAYA-II in Connect Four whenever Dr. Macdonald thinks it's ready.