Moth



Blackwell Publishing

Epistasis

epistasis.jpg

Epistasis is the interaction between the genes at two or more loci, so that the phenotype differs from what would be expected if the loci were expressed independently.

It is important in population genetics when the fitness effects of a genotype depend on what genotype it is associated with at the other locus. It is in this situation that natural selection can maintain linkage disequilibrium in a population.

A good example of epistatic interaction is found in the case of the Papilio memnon butterfly, which is pictured opposite.

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