翻訳と辞書 Words near each other ・ Retrospective EPs ・ Retrospective I ・ Retrospective II ・ Retrospective memory ・ Retrospective Review ・ Retrospective think aloud ・ Retrospectively rated insurance ・ Retrospektivt collage ・ Retrospektïẁ (Part III) ・ Retrospektïẁ (Parts I+II) ・ Retrosplenial cortex ・ Retrostium ・ Retrosynthetic analysis ・ Retrotortina ・ Retrotranslator ・ Retrotransposon ・ Retrotransposon marker ・ Retrotronics ・ RetroUI ・ Retroversion of the sovereignty to the people ・ Retroverted uterus ・ Retroviral aspartyl protease ・ Retroviral matrix protein ・ Retroviral Psi packaging element ・ Retroviral ribonuclease H ・ Retrovirology (journal) ・ Retrovirus ・ Retrovirus direct repeat 1 (dr1) ・ Retrovirus RTS ・ Retrovisceral space Dictionary Lists mini英和辞書 mini和英辞書 Webster 1913 Latin-English FOLDOC Wikipedia English ウィキペディア

翻訳と辞書　辞書検索 [ 開発暫定版 ] スポンサード リンク Retrotransposon ： ウィキペディア英語版 Retrotransposon Retrotransposons (also called transposons via RNA intermediates) are genetic elements that can amplify themselves in a genome and are ubiquitous components of the DNA of many eukaryotic organisms. They are one of the two subclasses of transposon, where the other is DNA transposon, which does not involve an RNA intermediate. They are particularly abundant in plants, where they are often a principal component of nuclear DNA. In maize, 49–78% of the genome is made up of retrotransposons. In wheat, about 90% of the genome consists of repeated sequences and 68% of transposable elements. In mammals, almost half the genome (45% to 48%) is transposons or remnants of transposons. Around 42% of the human genome is made up of retrotransposons, while DNA transposons account for about 2–3%. ==Biological activity== The retrotransposons' replicative mode of transposition by means of an RNA intermediate rapidly increases the copy numbers of elements and thereby can increase genome size. Like DNA transposable elements (class II transposons), retrotransposons can induce mutations by inserting near or within genes. Furthermore, retrotransposon-induced mutations are relatively stable, because the sequence at the insertion site is retained as they transpose via the replication mechanism. Retrotransposons copy themselves to RNA and then back to DNA that may integrate back to the genome. The second step of forming DNA may be carried out by a reverse transcriptase, which the retrotransposon encodes. Transposition and survival of retrotransposons within the host genome are possibly regulated both by retrotransposon- and host-encoded factors, to avoid deleterious effects on host and retrotransposon as well, in a relationship that has existed for many millions of years between retrotransposons and their hosts. The understanding of how retrotransposons and their hosts' genomes have co-evolved mechanisms to regulate transposition, insertion specificities, and mutational outcomes in order to optimize each other's survival is still in its infancy. Because of accumulated mutations, most retrotransposons are no longer able to retrotranspose. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Retrotransposon」の詳細全文を読む スポンサード リンク 翻訳と辞書 : 翻訳のためのインターネットリソース Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.