A thermal cycle system and method suitable for mass production of DNA comprising a temperature control body having at least two sectors. Each sector has at least one heater, cooler, or other means for changing temperature. A path traverses the sectors in a cyclical fashion. In use, a piece of tubing or other means for conveying is placed along the path and a reaction mixture is pumped or otherwise moved along the path such that the reaction mixture is repetitively heated or cooled to varying temperatures as the reaction mixture cyclically traverses the sectors. The reaction mixture thereby reacts to form a product. In particular, polymerase chain reaction reactants may continuously be pumped through the tubing to amplify DNA. The temperature control body is preferably a single aluminum cylinder with a grooved channel circling around its exterior surface, and preferably has wedge-shaped or pie-shaped sectors separated by a thermal barrier.