Gene Interactions and Epistasis

What is the condition for the second gene to express its phenotype?

What type of epistasis is observed in the common carp?

What is the F2 phenotypic ratio for the fruit color in squash?

What type of epistasis occurs when the recessive alleles of one gene locus suppress the phenotypic expression of the alleles of another gene?

What is the F2 phenotypic ratio for the color of onion?

What type of epistasis is observed in the flower color of sweet pea?

What is the term used to describe the interaction between two or more genes that govern a single character?

What is the term used to describe a gene that suppresses or masks the action of another gene?

What is the result of the interaction between alleles at different loci?

What is the term used to describe the phenomenon where a dominant allele at one locus produces a particular phenotype, regardless of the genotype at the second locus?

What is an example of a set of phenotypes controlled by the epistatic interaction among four genes?

What is the term used to describe the gene that is suppressed by an epistatic gene?

Epistasis

Epistasis is a type of genetic interaction where one gene locus affects the expression of another gene locus, resulting in a complex interplay between genes that can influence the final phenotype of an organism, often leading to unpredictable outcomes.
It involves inter-genic suppression or the masking effect of one gene locus on another.

Types of Epistasis

Dominant Epistasis: A dominant allele at one locus produces a particular phenotype, regardless of the genotype at the second locus.
Recessive Epistasis: Recessive alleles of one gene locus suppress the phenotypic expression of the alleles of another gene.
Duplicate Recessive Epistasis: A type of recessive epistasis where the recessive alleles of two genes interact to produce a particular phenotype.

Examples of Epistasis

Common Carp: Scale pattern is controlled by dominant epistasis.
Chinook Salmon: Flesh color is controlled by dominant epistasis with a 12:3:1 phenotypic ratio.
Gold Fish: Albinism is controlled by duplicate recessive gene interaction.
Mexican Cave Characins: Eye color is controlled by recessive epistasis with a 9:3:4 phenotypic ratio.
Squash: Fruit color is controlled by dominant epistasis with a 9:3:1 phenotypic ratio.
Onion: Color is controlled by recessive epistasis with a 9:3:3:1 phenotypic ratio.
Sweet Pea: Flower color is controlled by duplicate recessive epistasis with a 9:7 phenotypic ratio.
Chicken: Comb type is controlled by epistasis with a 9:3:3:1 phenotypic ratio.
Siamese Fighting Fish: Body color is controlled by epistasis among four genes.

Key Concepts

Epistatic Locus: A gene locus that suppresses or masks the action of a gene at another locus.
Hypostatic Gene: A gene that is suppressed by an epistatic gene.
Non-Allelic or Intergenic Genetic Interactions: Independent genes that interact with one another to express a single phenotypic trait.

Learn about gene interactions, including non-allelic genetic interactions and epistasis, which involves inter-genic suppression or the masking effect of one gene locus on another.