What Does the Phenocopy Copy?

Abstract

The concept of the phenocopy is examined from the point of view of psychology. Two main uses are described: to refer to artificially induced versions of phenotypes usually associated with mutant genes and to designate naturally occurring alternate phenotypes which appear in different environments. It is argued that the traditional definition, an environmentally produced copy of a genetic character, perpetuates the misleading and invalid assumption that some phenotypic characters are programmed and formed by the genes, while others are formed by the environment. An alternate view rejects this developmental dichotomy (which is to be distinguished from the legitimate description of specific sources of variation under restricted experimental conditions), instead taking the notion of multiple developmental pathways as central. The value of this latter idea extends far beyond the phenocopy itself, emphasizing as it does the coaction, not just interaction as it is conventionally construed, of genome and environment in ontogenesis. In the light of this coaction the concept of genetic potential is scrutinized and found inadequate to the often unpredictable multiplicity of development.