Les \u00e9l\u00e9ments transposables sont des entit\u00e9s g\u00e9n\u00e9tiques souvent consid\u00e9r\u00e9es comme des parasites g\u00e9nomiques, du fait qu\u2019ils peuvent se r\u00e9pliquer plus rapidement que le g\u00e9nome qui les porte. La transposition de nouvelles copies d\u2019\u00e9l\u00e9ments transposables dans de nouveaux sites g\u00e9nomiques, ou la recombinaison ectopique entre copies, peut avoir des effets d\u00e9l\u00e9t\u00e8res \u00e9vidents sur le fonctionnement du g\u00e9nome et des g\u00e8nes. Les \u00e9l\u00e9ments transposables restent n\u00e9anmoins une force \u00e9volutive majeure, en augmentant la diversit\u00e9 g\u00e9n\u00e9tique, favorisant ainsi l\u2019adaptabilit\u00e9 des g\u00e9nomes.<\/p>\n
Comme tous les g\u00e8nes classiques, les \u00e9l\u00e9ments transposables sont soumis \u00e0 des r\u00e9gulations diverses qui vont limiter le nombre de copies dans le g\u00e9nome et dans les populations, et contrebalancer ainsi l\u2019augmentation du nombre de copies li\u00e9e \u00e0 la transposition. De plus, le nombre de copies est lui-m\u00eame soumis \u00e0 s\u00e9lection, d\u00e8s lors que le fardeau g\u00e9n\u00e9tique devient trop lourd.<\/p>\n
Comme tous les g\u00e8nes classiques, les s\u00e9quences des \u00e9l\u00e9ments transposables \u00e9voluent. Toutefois, la s\u00e9lection purifiante pour conserver une prot\u00e9ine fonctionnelle est moins forte, la transposition d\u2019une copie pouvant \u00eatre r\u00e9alis\u00e9e gr\u00e2ce aux enzymes fabriqu\u00e9es \u00e0 partir d\u2019une autre copie (transposition en trans <\/i>). Ainsi, de nombreuses copies inactives ou d\u00e9l\u00e9t\u00e9es peuvent s\u2019accumuler, et m\u00eame s\u2019amplifier. Il en r\u00e9sulte ainsi une comp\u00e9tition entre copies d\u2019un m\u00eame \u00e9l\u00e9ment, qui s\u2019ajoute \u00e0 la comp\u00e9tition entre familles diff\u00e9rentes dans un m\u00eame g\u00e9nome.<\/p>\n","protected":false},"excerpt":{"rendered":"
Les \u00e9l\u00e9ments transposables sont des entit\u00e9s g\u00e9n\u00e9tiques souvent consid\u00e9r\u00e9es comme des parasites g\u00e9nomiques, du fait qu\u2019ils peuvent se r\u00e9pliquer plus rapidement que le g\u00e9nome qui les porte. La transposition de nouvelles copies d\u2019\u00e9l\u00e9ments transposables dans de nouveaux sites g\u00e9nomiques, ou la recombinaison ectopique entre copies, peut avoir des effets d\u00e9l\u00e9t\u00e8res \u00e9vidents sur le fonctionnement du […]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"_themeisle_gutenberg_block_has_review":false,"footnotes":""},"class_list":["post-6041","page","type-page","status-publish","hentry"],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.egce.universite-paris-saclay.fr\/index.php?rest_route=\/wp\/v2\/pages\/6041","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.egce.universite-paris-saclay.fr\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.egce.universite-paris-saclay.fr\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.egce.universite-paris-saclay.fr\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.egce.universite-paris-saclay.fr\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=6041"}],"version-history":[{"count":0,"href":"https:\/\/www.egce.universite-paris-saclay.fr\/index.php?rest_route=\/wp\/v2\/pages\/6041\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.egce.universite-paris-saclay.fr\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=6041"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}