epistasis

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epistasis

 [ĕ-pis´tah-sis]
1. suppression of a secretion or excretion, as of blood, menses, or lochia.
2. the interaction between genes at different loci, as a result of which one hereditary character is unexpressed, or is masked by the superimposition of another upon it. See also dominance. adj., adj epistat´ic.

e·pis·ta·sis

(e-pis'tă-sis),
1. The formation of a pellicle or scum on the surface of a liquid, especially as on standing urine.
2. Phenotypic interaction of nonallelic genes.
3. A form of gene interaction whereby one gene masks or interferes with the phenotypic expression of one or more genes at other loci; the gene the express phenotype of which is said to be "epistatic," whereas the phenotype altered or suppressed is then said to be "hypostatic."
Synonym(s): epistasy
[G. scum; epi- + G. stasis, a standing]

epistasis

(ĭ-pĭs′tə-sĭs)
n. pl. epista·ses (-sēz′)
1. An interaction between nonallelic genes in which the genotype at one locus affects the expression of alleles at another locus.
2. A film that forms over the surface of a urine specimen.
3. The suppression of a bodily discharge or secretion.

ep′i·stat′ic (ĕp′ĭ-stăt′ĭk) adj.

epistasis

[epis′təsis]
Etymology: Gk, a standing
1 suppression of a secretion or excretion, as of blood, menses, or lochia.
2 an interaction between genes at different loci in which one gene masks or suppresses the expression of the other. Epistasis, which is nonallelic and therefore different from dominance, may be caused by the presence of homozygous recessive alleles at one gene pair, as occurs in the Bombay phenotype, or by the presence of a dominant allele at one locus that counteracts the expression of a dominant allele at the other locus. Compare dominance. epistatic, adj.

e·pis·ta·sis

(e-pis'tă-sis)
1. The formation of a pellicle or scum on the surface of a liquid, especially on standing urine.
2. Phenotypic interaction of nonallelic genes.
3. A form of gene interaction whereby one gene masks or interferes with the phenotypic expression of one or more genes at other loci; the gene with the expressed phenotype is said to be epistatic, the phenotype altered or suppressed is then said to be hypostatic.
[G. scum; epi- + G. stasis, a standing]
Epistasisclick for a larger image
Fig. 152 Epistasis . The interaction of genes A and B.

epistasis

a form of genetic interaction in which one gene interferes with the expression of another gene, as when, for example, genes A and B code for enzymes active in the same PATHWAY. See Fig. 152 . If both ALLELES of gene A code for a nonfunctional version of enzyme A, then the pathway will shut down, irrespective of which B alleles are present, i.e. gene A is epistatic to gene B. Compare DOMINANT EPISTASIS, RECESSIVE EPISTASIS.

epistasis,

n gene interaction where a gene at a particular locus supercedes or obscures the expression of another gene at a different locus.

e·pis·ta·sis

(e-pis'tă-sis)
Formation of a pellicle or scum on the surface of a liquid, especially as on standing urine.
[G. scum; epi- + G. stasis, a standing]

epistasis

non-allelic masking of one gene by another, e.g. the masking of the black gene by the orange gene in tortoiseshell cats.
References in periodicals archive ?
Otherwise, inferences on genetic interactions using RPM would not help determine whether their results would have viable implication to biological genetic interaction.
Consequently, development of appropriate and efficient methods to assess genetic interactions would be an urgent task to achieve essential understanding of their genetic architecture.
The potential interaction effects have not been analyzed in many genetic studies of complex traits because of the increasing number of genetic interaction parameters (Frankel and Schork, 1996).
In this article, we are, however, focusing on a classical meaning of genetic interaction that a genotypic effect at a gene is influenced by another genotype at another gene on the same genome (Falconer and Mackay, 1996).
The methods for estimating genetic interaction effects were recently proposed by a nonparametric approach of grouping multi-locus genotypes to overcome the problems in the analysis with the conventional genetic interaction model.
This clearly demonstrates that even with 3 loci, evaluating genetic interaction effects with CPM requires too exhaustive computing.
Such false positives or false negatives are more likely to be increased without a plausible biological explanation of grouping when applying the partitioning-based estimation of genetic interaction effects.
Unclear biological explanation on grouping multi-locus genotypes in CPM or RPM led to skepticism about the plausibility of the grouping-based algorithm, which guided back to a parametric method for explaining genetic interaction effects.
Inverse Gamma distributions were assumed for the priors of variance components for both genetic interaction effects and residuals because the use of flat priors for variance components might lead to inferences based on theoretically nonexistent posterior distributions (Hobert and Casella, 1996).
g] is the shape parameter for genetic interaction variance component, and [[gamma].
The posterior mean of the genetic interaction effects is recommended to be estimated based on the optimum Bayes decision rule under quadratic loss.
Such research could include the evolution of haplotypes, selection for genetic interactions, and the evolution of recombination and methylation patterns.