plei·o·trop·ic \|plīə.|träpik\adjective Etymology:pleio- + -tropic of a gene: producing more than one effect : having multiple phenotypic expressions < a pleiotropic gene that induces shortening of the ear and reduces general body size has been reported in the mouse > • plei·o·trop·i·cal·ly\-pə̇k(ə)lē\adverb