complementation

1. Functional interaction between two defective viruses permitting replication under conditions inhibitory to the single virus. 2. Interaction between two genetic units, one or both of which are defective, permitting the organism containing these units to function normally, whereas it could not do so if either unit were absent.

- intergenic c. c. between pieces of genetic material that regulate the same function, such as a multienzyme pathway, but have defects in regions of separate genetic function; such c. permits synthesis of a normal end-product.

- intragenic c. c. between pieces of genetic material, each of which has a different defect within the same locus; the resultant product of each is defective and nonfunctional, but the defective products may associate to produce a product which has some activity.

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com·ple·men·ta·tion .käm-plə-(.)men-'tā-shən, -mən- n

1) the formation of neutral colors from complementary colors

2) production of normal phenotype in an individual heterozygous for two closely related mutations with one on each homologous chromosome and at a slightly different position

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com·ple·men·ta·tion (kom″plə-men-taґshən) [L. complēre to fill out or up] the interaction between two sets of genes introduced into the same cell, such that the cell can function even though each set of genes carries a mutated, nonfunctional gene; it indicates that the defects are not identical.