The degree to which a genotype is expressed in the phenotype— may be affected by the environment.
Some diseases are very predictable in terms of age of onset and severity of symptoms. Such a disease is typically “expressed” in the same way in each affected individual. But some conditions, for example Toller PRA, don’t fit this description. They might have very different ages of onset, different degrees of severity, and/or different rates of progression even within the same line, the same pedigree, or even the same litter. One confusing result of reduced or variable expressivity is that a dog can be affected according to a DNA test, yet show no clinical signs of disease until much later, or show only mild and slowly progressing clinical signs of the disease. This dog must not be confused with a case of false positive.
The variation of phenotype that occurs with a particular genotype. Example: Variations of merle patterning or spot shape and distribution on piebald animals..
Refers to the range of disease severity caused by a particular gene mutation.
Variation in the severity of the phenotypic features of a particular gene.
the degree to which a mutant gene is expressed; variable expressivity is characteristic of autosomal dominant diseases
Variation in the severity of a genetic trait.
the range of phenotypes expressed by a given genotype under any given set of environmental conditions, or over a range of environmental conditions
In genetics, the degree of clinical manifestation of a trait or characteristic.
Degree of expression of a genotype in the phenotype.
Pertaining to observed quantitative differences in the expression of a phenotype among individuals that have the same mutant genotype. When quantitative differences are observed, a phenotype is said to show "variable expressivity" which can be caused by environmental factors, modifier genes or chance.
The degree of manifestation of a certain character in the offspring. The degree of expression of a given gene. Genes that always produce the same phenotype have 100 percent expressivity.
The extent to which an inherited trait from a gene appears in an individual. The degree of expressivity varies in the individuals who carry the gene.
The degree of expression of a mutant phenotype.
variation in allelic expression when the allele is penetrant. Not all traits are expressed 100% of the time even though the allele is present. For example the dominant allele P produces polydactyly in humans, a trait that is characterized by extra toes and/or fingers. Two normal appearing adults have been known to mate and produce offspring that express polydactyly. Thus one parent must carry at least one dominant allele (P allele) and its genotype is probably Pp. This parent with the Pp genotype exhibits reduced penetrance for the P allele.
Expressivity refers to variations of a phenotype in genetics. The term is used to qualitatively characterize the variance or extent of the phenotype. For example a quantitative trait - like body height - might have large variance and therefore can make prediction of the phenotype difficult.