Expressivity is a term used in genetics that refers to variations of a phenotype in individuals carrying a particular genotype. The term can be used to qualitatively or quantitatively characterize the extent of the phenotype variation given a particular genotype. The term is equivalent to the severity of a condition in clinical medicine. For example, the amount of blood ejected from the pumping heart with each contraction can be quantitated by echocardiography and is called the ejection fraction. If a specific genotype is associated with the development of congestive heart failure, the expressivity would be represented by the range of ejection fractions seen in patients that have that genotype. As a more qualitative example, the "blue" gene might have an expressivity of 25% for individuals that express the "blue" gene and appear light blue, and 75% for individuals that express the "blue" gene and appear dark blue. This differs from penetrance in that penetrance refers to the likelihood of the gene generating any phenotype at all, while expressivity refers to the influence of an expressed gene in individuals. "Variable expressivity" occurs when a phenotype is expressed to a different degree among individuals with the same genotype. For example, individuals with the same allele for gene involved in a quantitative trait like body height might have large variance (some are taller than others), making prediction of the phenotype from a particular genotype alone difficult. The expression of a phenotype may be modified by the effects of aging, other genetic loci or environmental factors.

ee also

*Mendelian inheritance

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  • expressivity — expressivity. См. экспрессивность. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • expressivity — [eks΄pres siv′ə tē] n. 1. the quality of being expressive 2. Genetics the relative degree to which a trait caused by a gene is manifested in an individual …   English World dictionary

  • Expressivity — The consistency of a genetic disease. For example, Marfan disease shows variable expressivity. Some persons with Marfan s merely have long fingers and toes while others have the full blown disease with dislocation of the lens and dissecting… …   Medical dictionary

  • expressivity — Degree of expression of a trait controlled by a particular gene. The gene may show different degrees of expression in different individuals. See: variable expressivity …   Glossary of Biotechnology

  • expressivity — expressive ► ADJECTIVE 1) effectively conveying thought or feeling. 2) (expressive of) conveying (a quality or idea). DERIVATIVES expressively adverb expressiveness noun expressivity noun …   English terms dictionary

  • expressivity — ˌekˌspreˈsivəd.ē, vətē, i noun ( es) Etymology: International Scientific Vocabulary expressive + ity; originally formed as German expressivität 1. : the relative capacity of a gene to modify the organism of which it is a part compare penetrance …   Useful english dictionary

  • expressivity — noun (plural ties) Date: 1934 1. the relative capacity of a gene to affect the phenotype of the organism of which it is a part 2. the quality of being expressive …   New Collegiate Dictionary

  • expressivity — /ek spre siv i tee/, n. 1. the quality or state of being expressive. 2. Genetics. the degree to which a particular gene produces its effect in an organism. Cf. penetrance. [1930 35; < G Expressivität. See EXPRESSIVE, ITY] * * * …   Universalium

  • expressivity — noun a) the quality of being expressive b) the degree to which a gene affects an organism …   Wiktionary

  • expressivity — (Roget s Thesaurus II) noun Vivid, effective, or persuasive communication in speech or artistic performance: articulacy, articulateness, eloquence, eloquentness, expression, expressiveness, facundity. See WORDS …   English dictionary for students

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