genocopy, the appearance of similar phenotypic characters due to genes located in different parts of a chromosome or in different chromosomes (so-called mutant alleles). The genocopy phenomenon, established primarily in higher organisms, is indicative of the complexity of inheritance of many characters. The biochemical nature of genocopy rests on the fact that the cell has several parallel methods of synthesizing its components. (For example, in a bacterial cell thymidylic acid can be synthesized either from uridylic or cytidylic acid.) Various mutations whose effect is realized through the same process or organ can copy one another in their final effect with different degrees of completeness; their final effect can be copied, in turn, by the action of various external factors (phenocopy). The phenomena of genocopy and phenocopy are very important for understanding the mechanisms of realization of hereditary (with genocopies) and nonhereditary (with phenocopies) anomalies and diseases in man.
V. N. SOIFER and V. P. EFROIMSON