{"id":6088,"date":"2019-04-10T12:37:45","date_gmt":"2019-04-10T10:37:45","guid":{"rendered":"https:\/\/ellipse.prbb.org\/?p=6088"},"modified":"2024-06-03T11:43:02","modified_gmt":"2024-06-03T09:43:02","slug":"epigenetica-mes-enlla-dels-gens","status":"publish","type":"post","link":"https:\/\/ellipse.prbb.org\/ca\/epigenetica-mes-enlla-dels-gens\/","title":{"rendered":"Epigen\u00e8tica, m\u00e9s enll\u00e0 dels gens"},"content":{"rendered":"<p><em>Epi, <\/em>en grec, significa \u2018damunt\u2019. Per aix\u00f2 s\u2019anomena <strong>epigen\u00e8tica&nbsp;<\/strong>a l\u2019estudi de tot all\u00f2 que est\u00e0 \u2018damunt\u2019 dels gens, la part de l\u2019her\u00e8ncia que no ve determinada per la seq\u00fc\u00e8ncia d&#8217;ADN. En altres paraules, \u00e9s una <strong>capa d\u2019informaci\u00f3 addicional que controla la regulaci\u00f3 dels gens per\u00f2 que no ve codificada per la seq\u00fc\u00e8ncia <a href=\"https:\/\/ellipse.prbb.org\/ca\/adn-la-base-molecular-de-la-vida\/\" target=\"_blank\" rel=\"noopener noreferrer\">d&#8217;ADN<\/a><\/strong>.<\/p>\n<p>Un dels fen\u00f2mens m\u00e9s coneguts de l\u2019epigen\u00e8tica \u00e9s la <strong>metilaci\u00f3 de l&#8217;ADN<\/strong>. L&#8217;ADN est\u00e0 format per combinacions de 4 nucle\u00f2tids:<\/p>\n<ul>\n<li>adenina (A)<\/li>\n<li>timina (T)<\/li>\n<li>guanina (G)<\/li>\n<li>citosina (C)<\/li>\n<\/ul>\n<p>Aquest \u00faltim nucle\u00f2tid pot ser modificat afegint-hi un<strong> grup metil (CH<sub>3<\/sub>)<\/strong>. Aix\u00f2 \u00e9s el que s\u2019anomena <strong>metilaci\u00f3<\/strong>, i t\u00e9 com a conseq\u00fc\u00e8ncia un canvi en l\u2019expressi\u00f3 del gen que ha estat modificat. Aix\u00ed, un cop un gen ha estat metilat la seva expressi\u00f3 generalment queda inhibida.<\/p>\n<p>Un altre tipus de canvi epigen\u00e8tic \u00e9s la <strong>modificaci\u00f3 de les histones<\/strong>, unes prote\u00efnes associades a l&#8217;ADN i que junt amb aquest conformen la <strong>cromatina<\/strong>. Les histones, com l&#8217;ADN, poden ser <strong>metilades<\/strong>, per\u00f2 tamb\u00e9 <strong>acetilades<\/strong>, afegint-hi un <strong>grup acetil (CH<sub>3<\/sub>CO)<\/strong>, o <strong>fosforilades<\/strong> amb un <strong>grup fosfat (PO<sub>4<\/sub>)<\/strong>. Qualsevol d\u2019aquestes modificacions canvia l\u2019estructura de les histones i, per tant, de la cromatina que compacta fins a 10.000 vegades a l&#8217;ADN.<\/p>\n<p>&nbsp;<\/p>\n<blockquote><p>Les modificacions epigen\u00e8tiques com la metilaci\u00f3 de l&#8217;ADN o la fosforilaci\u00f3, l&#8217;acetilaci\u00f3 i la metilaci\u00f3 de les histones, poden inhibir o activar l&#8217;expressi\u00f3 de gens.<\/p><\/blockquote>\n<p>&nbsp;<\/p>\n<p>La combinaci\u00f3 d\u2019aquestes modificacions epigen\u00e8tiques juga un paper important en l\u2019<strong>\u201dimprinting\u201d (o imprenta gen\u00e8tica)<\/strong>, que \u00e9s una marca que fa que un mateix gen s\u2019expressi o no segons si prov\u00e9 del g\u00e0meta femen\u00ed o del mascul\u00ed.<\/p>\n<p>I quina import\u00e0ncia tenen aquests fen\u00f2mens?&nbsp;Per una banda ajuden a explicar les difer\u00e8ncies entre bessons id\u00e8ntics, persones que comparteixen la mateixa seq\u00fc\u00e8ncia d&#8217;ADN per\u00f2 que poden tenir diferents variants epigen\u00e8tiques (un dels dos bessons pot tenir determinats gens inhibits per la metilaci\u00f3, per exemple).<\/p>\n<p>Per\u00f2, a m\u00e9s, <strong>la \u2018capa\u2019 epigen\u00e8tica de la informaci\u00f3 resulta crucial per al desenvolupament, el creixement i l\u2019envelliment de totes les persones<\/strong>. Els canvis epigen\u00e8tics tamb\u00e9 estan involucrats amb el <a href=\"https:\/\/ellipse.prbb.org\/ca\/joan-albanell-de-cancer-de-mama-no-nhi-ha-nomes-un\/\" target=\"_blank\" rel=\"noopener noreferrer\">c\u00e0ncer<\/a>. En els darrers anys s\u2019ha vist que les pertorbacions de l\u2019estructura de la cromatina i altres fen\u00f2mens epigen\u00e8tics poden causar una expressi\u00f3 de gens inadequada que doni lloc a un creixement cel\u00b7lular maligne.<\/p>\n<p>&nbsp;<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-6203 size-full aligncenter\" src=\"https:\/\/ellipse.prbb.org\/wp-content\/uploads\/2019\/03\/epigen-5c-c3-a8_37773527.png\" alt=\"\" width=\"800\" height=\"1554\" srcset=\"https:\/\/ellipse.prbb.org\/wp-content\/uploads\/2019\/03\/epigen-5c-c3-a8_37773527.png 800w, https:\/\/ellipse.prbb.org\/wp-content\/uploads\/2019\/03\/epigen-5c-c3-a8_37773527-115x224.png 115w, https:\/\/ellipse.prbb.org\/wp-content\/uploads\/2019\/03\/epigen-5c-c3-a8_37773527-768x1492.png 768w, https:\/\/ellipse.prbb.org\/wp-content\/uploads\/2019\/03\/epigen-5c-c3-a8_37773527-309x600.png 309w\" sizes=\"auto, (max-width: 800px) 100vw, 800px\" \/><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Sense modificar el codi de l&#8217;ADN, l&#8217;epigen\u00e8tica pot alterar l&#8217;expressi\u00f3 dels nostres gens.<\/p>\n","protected":false},"author":2,"featured_media":6197,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[30],"tags":[275,297,513,648,289],"new-type":[35],"class_list":["post-6088","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-ciencia-i-societat","tag-adn","tag-biologia-molecular","tag-ciencia-al-descobert","tag-epigenetica","tag-genoma","new-type-noticies"],"acf":[],"_links":{"self":[{"href":"https:\/\/ellipse.prbb.org\/ca\/wp-json\/wp\/v2\/posts\/6088","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ellipse.prbb.org\/ca\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ellipse.prbb.org\/ca\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ellipse.prbb.org\/ca\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/ellipse.prbb.org\/ca\/wp-json\/wp\/v2\/comments?post=6088"}],"version-history":[{"count":5,"href":"https:\/\/ellipse.prbb.org\/ca\/wp-json\/wp\/v2\/posts\/6088\/revisions"}],"predecessor-version":[{"id":42894,"href":"https:\/\/ellipse.prbb.org\/ca\/wp-json\/wp\/v2\/posts\/6088\/revisions\/42894"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/ellipse.prbb.org\/ca\/wp-json\/wp\/v2\/media\/6197"}],"wp:attachment":[{"href":"https:\/\/ellipse.prbb.org\/ca\/wp-json\/wp\/v2\/media?parent=6088"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ellipse.prbb.org\/ca\/wp-json\/wp\/v2\/categories?post=6088"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ellipse.prbb.org\/ca\/wp-json\/wp\/v2\/tags?post=6088"},{"taxonomy":"new-type","embeddable":true,"href":"https:\/\/ellipse.prbb.org\/ca\/wp-json\/wp\/v2\/new-type?post=6088"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}