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Related to phenocopies: pleiotropy, genocopy


The nonhereditary alteration of a phenotype to a form imitating a mutant trait; caused by external conditions during development.



a nonhereditary change in a phenotype, induced by specific environmental conditions and mimicking of some known hereditary change, or mutation, as exhibited in the phenotype. For example, nonhereditary teratism, or monstrosities, may be induced in the genetically normal embryos and larvae of some insects by various means, including high temperatures and vaporized ether; examples of such monstrosities, which may be observed in adult individuals, are a change in the number of legs or wings or the transformation of antennae into legs. These monstrosities are phenocopies of similar but hereditary changes that normally develop, in the absence of any external influence, in a number of mutant insect strains.

Phenocopies of various mutuations may be experimentally induced in other species of animals and plants as well. As a rule, the possible range of such phenocopies is not determined by the nature of the operative factor, but rather by the stage of development of the experimental organism. Presumably, some external factor that produces phenocopies in normal individuals interferes with the activity of the corresponding normal genes, resulting in the appearance of a mutant phenotype. The study of phenocopies is thus an important field of inquiry for phenogenetic research.


Lobashev, M. E. Genetika. Leningrad, 1967.
Goldschmidt, R. B. Physiological Genetics. New York, 1938.


References in periodicals archive ?
Here, we extend these observadons to show that a) developmental exposure to the NDL PCB-95 in the maternal diet phenocopies the effect of developmental Al254 exposure on dendritic arborization in the developing hippocampus, b) PCB-95 promotes dendritic growth in cultured hippocampal neurons at picomolar to nanomolar concentrations, and c) the dendrite-promoting activity of PCB-95 requires RyR activity.
45,129,130) It is, therefore, not surprising that some authors have hypothesized that basal-like cancers not only make phenocopies of tumors arising in BRCA1 mutation carriers but also harbor the same defects in DNA repair mechanisms.
Phenocopies in BRCA1 and BRCA2 families: evidence for modifier genes and implications for screening.
As well, there is a lack of correspondence between the inherited genotype(s) and the resultant phenotype(s), which may be due to incomplete penetrance of predisposing loci or to phenocopies, that is disease that develops in the absence of apparent genetic risk factors.