Position effect

Position effect

Position effect is the effect on the expression of a gene when its location in a chromosome is changed, often by translocation. This has been well described in "Drosophila" with respect to eye color and is known as position effect variegation (PEV). [cite journal |author=Weiler K, Wakimoto B |title=Heterochromatin and gene expression in Drosophila |journal=Annu Rev Genet |volume=29 |issue= |pages=577–605 |year= |pmid=8825487 |doi=10.1146/annurev.ge.29.120195.003045]

The phenotype is well characterised by unstable expression of a gene that results in the red eye coloration. In the mutant flies the eyes typically have a mottled appearance of white and red sectors. These phenotypes are often due to a chromosomal translocation such that the color gene is now close to a region of heterochromatin. The heterochromatin can spread stochastically and switch off the color gene resulting in the white eye sectors.

"Position effect" is also used to describe the variation of expression exhibited by identical transgenes that insert into different regions of a genome. In this case the difference in expression is often due to enhancers that regulate neighboring genes. These local enhancers can also effect the expression pattern of the transgene. Since each transgenic organism has the transgene in a different location each transgenic organism has the potential for a unique expression pattern.


External links

* [http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mboc4.figgrp.665 Position effect explained on "Molecular Biology of the Cell"]

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  • position effect — position effect. См. эффект положения. (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.

  • position effect — padėties efektas statusas T sritis augalininkystė apibrėžtis Genų veiklos priklausymas nuo erdvinio jų išsidėstymo. atitikmenys: angl. position effect rus. эффект положения …   Žemės ūkio augalų selekcijos ir sėklininkystės terminų žodynas

  • Position-effect variegation — is a variegation caused by the inactivation of a gene in some cells through its abnormal juxtaposition with heterochromatin.The classical example is the Drosophila w [m4] (speak white mottled 4) translocation. In this mutation, an inversion on… …   Wikipedia

  • position effect — Effect on the expression of a gene depending upon its position relative to other genes on the chromosome. Moving (transposing) a gene from an inactive region to an active region can alter expression markedly sometimes with unfortunate… …   Dictionary of molecular biology

  • Position effect variegation — Die Positionseffekt Variegation (PEV) ist ein Phänomen in der Genetik. Inhaltsverzeichnis 1 Entdeckung 2 Siehe auch 3 Einzelnachweise 4 Literatur // …   Deutsch Wikipedia

  • position effect — noun (genetics) the effect on the expression of a gene that is produced by changing its location in a chromosome • Topics: ↑genetics, ↑genetic science • Hypernyms: ↑consequence, ↑effect, ↑outcome, ↑ …   Useful english dictionary

  • position effect — noun Date: 1930 a genetic effect in which the expression of a gene is influenced by its interaction with usually adjacent genes and which is modified when the spatial relationships of the genes change (as by translocation) …   New Collegiate Dictionary

  • position effect — The influence of the location of a gene (particularly a transgene) on its expression and hence its effect on phenotype …   Glossary of Biotechnology

  • position effect — The difference in the phenotypic expression of a gene due to a change in their position with respect to other genes on the chromosome …   Dictionary of invertebrate zoology

  • position effect — in genetics, the change in expression of a gene as a function of a change in its position relative to that of other genes …   Medical dictionary

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