mu·ta·gen (myōō'tə-jən, -jěn') n. An agent, such as a chemical, ultraviolet light, or a radioactive element, that can induce or increase the frequency of mutation in an organism.
[muta(tion) + -gen.] mu'ta·gen'ic adj., mu'ta·gen'i·cal·ly adv., mu'ta·ge·nic'i·ty (-jə-nĭs'ĭ-tē) n.