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Complementation (genetics)

The complementary action of different genetic factors. The term usually implies two homologous chromosomes or chromosome sets, each defective because of mutation and unable by itself to promote the normal development or metabolism of the organism, but able to do so jointly when brought together in the same cell. See Chromosome, Mutation

S. Benzer proposed the term cistron for the unit within which mutants do not complement each other. The word gene is often used in the same sense. The usual biochemical function of a cistron, or gene, is to determine the structure of a specific polypeptide component of a protein. Full complementation between different genes is the rule except when, as sometimes in bacteria, the genes form part of a functionally coordinated complex (operon). Allelic mutants (mutants within one gene) show limited complementation in some cases, for example, when certain pairs of mutant polypeptides correct each other's defects through coaggregation in a complex protein. See Genetics, Operon



in genetics, the complementary action of two alleles of a single gene or two different genes of the same chromosomal set.

Interallelic complementation is associated with the synthesis in heterozygotes of two different but functionally similar protein molecules instead of the one protein molecule of homozygotes. Moreover, heterozygotes often have hybrid protein molecules made of polypeptide chains that are synthesized under the control of two different alleles. In heterozygotes with defective mutant alleles, complementation may be expressed in a restoration of the ability to synthesize a normally functioning protein—an ability that would be partly or wholly lost to each mutant separately.

Interallelic complementation seems to be the main cause of monogenic heterosis—the superiority of heterozygotes over homozygotes in viability and rate of growth. Detailed complementation charts have been constructed for the genes of certain viruses, bacteria, and fungi.

Intergenic complementation is a manifestation of the interaction of nonallelic genes (epistasis), whereby a defect expressed in the impairment of a given metabolic process is compensated by other genes. The term “complementarity” is sometimes used in biological literature in a sense similar or identical to complementation.


Fincham, J. Geneticheskaia komplementatsiia. Moscow, 1968. (Translated from English.)



The act of replacing a set by its complement.
References in periodicals archive ?
2004) Identification of a new complementation group of the peroxisome biogenesis disorders and PEX14 as the mutated gene.
The auxiliary features are the uninflected form dare in 3rd person singular and simple past, the lack of non-finite forms, the use of direct not negation or clitic n't, the subject-verb inversion strategy and the selection of BI complementation.
Complementation of this [DELTA]tolC restored to ability to invade human macrophage cell similar to their wild-type parents' strains this result conformed that tolC play role in during invasion of S.
Odyssey Thera has established the dominant worldwide intellectual property position in Protein-fragment Complementation Assays, encompassing 16 issued US and international patents and over 60 applications in prosecution.
4] Nonstandard abbreviations: TSH, thyroid-stimulating hormone; TSI, thyroid-stimulating immunoglobulin; EFC-cAMP, cAMP XS enzyme fragment complementation.
One possible way to account for the meaning differences associated with the use of different complementation patterns, as described in the previous section, is to assume that these differences are determined by the complement-taking predicate.
I probably don't know you any more, Complementation is just an implication That we are choosing to ignore.
50 deductible for ambulatory care, suggesting a trend toward a complementation effect between ambulatory and inpatient care (Phelps 1992).
Although there is no obvious complementation by her sire Sadler's Wells, her closer family boasts Rule Of Law and stamina should not be an issue.
True socio-economic balance of the North Alabama Region will require rousing exchange and complementation between the demographic, social, and economic growth potential.

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