Submitted to: Encyclopedia of Animal Science
Publication Type: Monograph
Publication Acceptance Date: 10/1/2007
Publication Date: 1/15/2008
Citation: Coleman, S.W., Brown, M.A. 2008. Animal Genotype x Environment Interactions [abstract]. Encyclopedia of Animal Science. Available http://www.informaworld.com/smpp/content~db=all?content=10.1081/E-EAS-120043010
Interpretive Summary: Genetic x environment interactions occur in both natural and domesticated populations of animals. Gene action for different physiological mechanisms may be suppressed or expressed as impacted by the environment. Generally in domesticated animals, the action is an environmental suppression of genetic potential but other mechanisms clearly exists. It is reasonable to conclude that differences among genotype more often than not depend on the production environment in which they are managed.
Technical Abstract: While genetics define the potential of an animal, the expression of those genetics is often modified by the environment in which the animal exists. Environmental effects may modify genetic expression of a trait uniformly across all possible genotypes or the amount of modification may be specific to particular genotypes. When environmental modifications are specific to particular genotypes, differences between genotypes will not be consistent across environments. This is called genotype by environment interaction (GxE). At the cellular level, GxE is probably a function of the environment either initiating or suppressing the expression of one or more genes. Environmental effects may cause the protein coded by a given gene to be produced in various amounts or not produced at all. Fitness to an environment can occur in animals that have inherited genes compatible with the environment, or in animals that have inherited genes that may be expressed over multiple environments. Genetic x environment interactions have been observed both in wild and in domesticated animals. Examples in pigs, poultry, and cattle generally show that as man has increased genetic selection intensity for productivity, animals with high genetic potential may not function consistent with their potential across multiple environments. In a challenging environment they may not function even as well as animals that may have lower genetic potential but that have wider capabilities for adaptation.