Neomorph - definition

Neomorph - an anatomical feature not derived from a feature found in an ancestor, but instead a new development

A neomorphic mutation causes a dominant gain of gene function that is different from the normal function.

Medical Definition of neomorph. 1: a structure that is not derived from a similar structure in an ancestor. 2: a mutant gene having a function distinct from that of any nonmutant gene of the same locus.