Lampbrush chromosome

Lampbrush chromosome

A Lampbrush chromosome (first seen by Flemming in 1882) is a large chromosome (largest) found especially in the oocytes (immature eggs) of most animals, except mammals. Lampbrush chromosomes occur during the diplotene stage of meiosis I. Lampbrush chromosomes are meiotic bivalents, each consisting of 2 sister chromatids. Each halve-bivalent is represented by two long strands that form many brushlike loops along the main axis of the chromosome. The outgrowths make DNA available for transcription during the maturation of the egg. Usually there is a little gene expression at meiosis, so it is not so easy to identify the activities of individual genes. Giant chromosomes in the lampbrush form can solve this problem, since they allow the individual transcription units to be examined. Lampbrush and chromosomal puffs in a cell indicate that the transcription of mRNA is taking place.

For more information see http://www.projects.ex.ac.uk/lampbrush/


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  • lampbrush chromosome — lampbrush chromosome. См. хромосомы типа ламповых щеток. (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.

  • lampbrush chromosome — ˈ ̷ ̷ˌ ̷ ̷ noun Etymology: translation of German lampenbürstenchromosom : a greatly enlarged pachytene chromosome having apparently filamentous granular loops extending from the chromomeres that is especially characteristic of certain animal… …   Useful english dictionary

  • lampbrush chromosome — lamp·brush chromosome .lamp .brəsh n a greatly enlarged diplotene chromosome that has apparently filamentous granular loops extending from the chromomeres and is characteristic of some animal oocytes * * * a giant chromosome with hundreds of… …   Medical dictionary

  • lampbrush chromosome — noun Date: 1911 a greatly enlarged diplotene chromosome that has apparently filamentous granular loops extending from the chromomeres and is characteristic of some animal oocytes …   New Collegiate Dictionary

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  • Chromosome — For a non technical introduction to the topic, see Introduction to genetics. Diagram of a replicated and condensed metaphase eukaryotic chromosome. (1) Chromatid – one of the two identical parts of the chromosome after S phase. (2)… …   Wikipedia

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  • Polytene chromosome — Polytene chromosomes in a Chironomus salivary gland cell …   Wikipedia

  • giant chromosome — 1. polytene c. 2. lampbrush c …   Medical dictionary

  • Cromosoma — Vista general de las células en un ápice de raíz de cebolla (Allium cepa), observado con 800 aumentos. (a) Célula sin dividirse, obsérvese la red de cromatina …   Wikipedia Español

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