What is the difference between epistasis and complementation

All Chapters Ch. Epistasis and Complementation See all sections. Next Section Variations of Dominance. Concept 1: Complementation. Mark as complete. Report issue.

Concept 2: Non-Epistatic Genes. Concept 3: Epistatic Genes. Concept 4: Other Gene Interactions. Practice: When performing a complementation test, how do you know if two mutations complement? Practice: How can you tell if two genes are epistatic? Videos in Epistasis and Complementation Concept 1: Complementation. Practice 4: Epistatic Ratio 2. Practice 5: Bombay Phenotype.

Previous Section Pleiotropy. Enter your friends' email addresses to invite them:. We invited your friends! Log in with Facebook. Log in with Gmail. Don't have an account? Sign up! Worksheet Download the video lesson worksheet Start. Understanding Independent Assortment. Chi Square Analysis. This test can be used to determine whether the mutations in two strains are in different genes as complementation ordinarily will occur more weakly or not at all if the mutations are in distinct sites of the same gene.

The eye colour of Drosophila is is a good model to demonstrate the complementation test. There are mainly two types of epistatic interactions: recessive and dominant.

In the recessive epistasis, the recessive allele of one gene masks the effects of either allele of the second gene. On the other hand, in the dominant epistasis, the dominant allele of one gene masks the effects of either allele of the second gene. In epistasis, the interaction between genes is antagonistic, such that one gene masks the expression of the other gene. The alleles that are being masked is called hypostatic alleles.

The alleles doing masking is known as epistatic alleles. A well-known example of epistasis is pigmentation in mice. The wild type coat colour, agouti AA , is dominant to coloured fur aa.

Anyhow, a separate gene C is necessary for pigmentation production. A mouse with recessive c allele at this locus is unable to produce pigment and is albino regardless of the allele present in locus A. Therefore, the genotypes: AAcc, Aacc, and aacc, all produce the albino phenotype. In this case, the C gene is epistatic to the A gene. Epistasis can also occur when the dominant allele masks the expression at a separate gene, as mentioned earlier.

Fruit colour in summer squash is expressed in this way. The homozygous recessive expression of the W gene ww coupled with a homozygous dominant or heterozygous dominant expression of the Y gene YY or Yy in summer squash produces yellow fruit, while the wwyy both genes recessive genotype produces green fruit. However, if a dominant copy of the W gene is present in the homozygous or heterozygous form, the summer squash will be a white fruit regardless of the Y alleles.

The genes of an individual are not expressed isolated from one another, but they function in a common environment. Thus, it expects interactions between genes would occur. Complementation is a form of genetic interaction between non-allelic genes. For example, in complementation, when a normal copy of a gene is introduced into a cell that harbours a mutated copy, it corrects the genetic defect.

In epistasis, the effect of gene mutation is dependent on the presence and absence of mutations in one or more other genes, respectively termed as modifier genes. So, this is the key difference between complementation and epistasis. Complementation and epistasis are variations involving multiple genes.

Complementation is the production of wild type phenotype by a cell or an organism that contains two mutant genes.