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. Like penetrance in most instances expressivity is related to an allele or a mutation or more generally a genotype. In these instances expressivity denotes how well the phenotype can be predicted, given the genotype.

Notes

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The wording "variable expressivity" usually means high expressivity. An internet search reveals many vague definitions and usage is not consistent in the literature.

See also

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• Penetrance
• Allele
• Phenotype
• Genotype
• Mendelian inheritance

Population genetics

Expresivita | 表现度