Epistasis
Epistasis - Related Videos
02:31
Epistasis
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2026
In addition to multiple alleles at the same locus influencing traits, numerous genes or alleles at different locations may interact and influence phenotypes in a phenomenon called epistasis. For example, rabbit fur can be black or brown depending on whether the animal is homozygous dominant or heterozygous at a TYRP1 locus. However, if the rabbit is also homozygous recessive at a locus on the tyrosinase gene (TYR), it will have an unshaded coat that appears white, regardless of its TYRP1...
01:09
Epistasis Analysis
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2023
Although Mendel chose seven unrelated traits in peas to study gene segregation, most traits involve multiple gene interactions that create a spectrum of phenotypes. When the interaction of various genes or alleles at different locations influences a phenotype, this is called epistasis. Epistasis often involves one gene masking or interfering with the expression of another (antagonistic epistasis). Epistasis often occurs when different genes are part of the same biochemical pathway. The...
08:01
Oct4GiP Reporter Assay to Study Genes that Regulate Mouse Embryonic Stem Cell Maintenance and Self-renewal
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Cited by 7 •
2012
We describe a fluorescence reporter assay to quickly identify and characterize genes that regulate mouse embryonic stem cell maintenance and self-renewal.
10:04
An Overview of Genetic Analysis
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2023
An organism’s physical traits, or phenotype, are a product of its genotype, which is the combination of alleles (gene variants) inherited from its parents. To varying degrees, genes interact with each other and environmental factors to generate traits. The distribution of alleles and traits within a population is influenced by a number of factors, including natural selection, migration, and random genetic drift.In this video, JoVE introduces some of the foundational discoveries in genetics,...
10:04
Mating and Tetrad Separation of Chlamydomonas reinhardtii for Genetic Analysis
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Cited by 35 •
2009
Mating and tetrad separation are required for genetic analysis in Chlamydomonas reinhardtii. Here we demonstrate standard methods for gametogenesis, mating, zygote germination and tetrad dissection. This protocol consists of an easy-to-follow series of steps that will make genetic approaches amenable to scientists who are less familiar with Chlamydomonas.
FAQs
Mendelian predictions often consider each locus separately, whereas epistasis reflects how loci function together. A mutation at one locus may prevent or modify the phenotype associated with a second locus, so allele combinations cannot be interpreted independently. This interaction changes the expected distribution of phenotypes and helps explain why genotype-to-phenotype relationships may be nonlinear.
Genes can act in the same biological pathway or network, linking their effects rather than producing independent outcomes. If one gene alters a step required for another gene’s effect, a mutation in the first locus can mask or change the phenotype associated with the second. Epistasis therefore provides a genetic view of functional relationships among biological components.
Recessive and dominant epistasis are classic forms distinguished by the genetic conditions under which one locus alters the effect of another. The distinction helps organize how masking or modification appears in inheritance patterns. Comparing these forms allows researchers to connect observed phenotype ratios with the underlying interaction between loci rather than treating each trait as the product of independent genes.
Complex traits may reflect the combined activity of genes rather than the isolated effect of any single locus. Epistatic relationships help account for cases in which the same genotype components produce different phenotypic outcomes depending on their genetic context. This makes epistasis relevant to interpreting quantitative traits and to understanding why simple one-gene explanations may be insufficient.
Genetic screens can reveal that the effect of one mutation changes in the presence of another mutation. Interpreting such results through epistasis helps distinguish direct single-gene effects from interactions within a pathway or network. This perspective is important because a masked or modified phenotype may otherwise be misread as evidence that the second gene has little or no biological role.
Epistasis provides a framework for examining how combinations of genetic variants may influence phenotypes, including disease susceptibility. Rather than evaluating loci in isolation, researchers can consider whether one genetic context changes the effect of another. This approach supports more informative interpretation of genomic data and can help explain variation that individual genetic factors do not fully account for.
During development, interacting genes can connect genetic variation to changes in biological pathways and resulting phenotypes. In evolutionary studies, these interactions help explain why the effect of a genetic change may depend on the presence of other variants. Examining epistasis therefore links gene interactions with developmental outcomes, evolutionary patterns, and the broader organization of biological systems.