Ke\u010f za\u010diatkom 90. rokov minul\u00e9ho storo\u010dia pri\u0161iel do k\u00edn film Stevena Spielberga, div\u00e1ci zostali v\u00a0nemom \u00fa\u017ease. Jedna z\u00a0najpam\u00e4tnej\u0161\u00edch sc\u00e9n, ktor\u00e1 zaujala mili\u00f3ny \u013eud\u00ed, vyobrazovala kom\u00e1ra z\u00a0doby dinosaurov uv\u00e4znen\u00e9ho v\u00a0skamenenej miazge \u2013 v jant\u00e1ri.<\/p>\n
V\u010faka krvi, ktor\u00e1 sa zachovala v tele tohto kom\u00e1ra, dok\u00e1zali z\u00edska\u0165 DNA t\u00fdchto prehistorick\u00fdch tvorov. Nielen\u017ee takto z\u00edskali poznatky o hist\u00f3rii a v\u00fdvoji na\u0161ej Zeme, ale z\u00e1rove\u0148 dok\u00e1zali naklonova\u0165 d\u00e1vne zvery pre \u00fa\u010dely Jursk\u00e9ho parku.<\/p>\n
Filmov\u00fa s\u00e9riu pochopite\u013ene zaraden\u00fd do \u017e\u00e1nru vedeckej fantastiky. To v\u0161ak neznamen\u00e1, \u017ee pomocou modernej vede sa k tomu nevieme dosta\u0165 bli\u017e\u0161ie. Ned\u00e1vno publikovan\u00e1 \u0161t\u00fadia v \u010dasopise Cell op\u00edsala nie\u010do, \u010do sa doteraz nikomu nepodarilo.<\/p>\n
Medzin\u00e1rodn\u00e9mu v\u00fdskumn\u00e9mu t\u00edmu sa toti\u017e podarilo zostavi\u0165 gen\u00f3m a 3D model chromoz\u00f3mov\u00fdch \u0161trukt\u00far 52-tis\u00edc rokov star\u00e9ho mamuta srstnat\u00e9ho. Ide o obrovsk\u00fd \u00faspech, preto\u017ee doposia\u013e sa vedcom podarilo z\u00edska\u0165 len fragmenty jeho DNA.<\/p>\n
Vedeck\u00fd \u010dasopis Nature uv\u00e1dza, \u017ee pribli\u017ene pred 40 rokmi vedci zistili, \u017ee zvy\u0161ky DNA sa m\u00f4\u017eu zachova\u0165 v exempl\u00e1roch z d\u00e1vnej minulosti. Napr\u00edklad v tis\u00edcro\u010dia star\u00fdch egyptsk\u00fdch m\u00fami\u00e1ch. Odvtedy v\u0161ak zistili, \u017ee n\u00e1js\u0165 ju m\u00f4\u017eu aj v \u010fal\u0161\u00edch pozostatkoch.<\/p>\n
Zaka\u017ed\u00fdm v\u0161ak narazili na probl\u00e9m. Ako \u010das plynie, DNA degraduje a\u00a0chemicky sa po\u0161kodzuje, \u010do sp\u00f4sobilo, \u017ee z\u00edskavali len fragmenty DNA bez ucelenej \u0161trukt\u00fary. \u00dapln\u00e1 rekon\u0161trukcia 3D gen\u00f3mu z\u00a0t\u00fdchto k\u00faskov je preto takmer nemo\u017en\u00e1.<\/p>\n V\u00fdskumn\u00edci tvrdia, \u017ee vzorka mamuta vznikla podobne ako vysu\u0161en\u00e9 hov\u00e4dzie m\u00e4so, tzv. beef jerky. Zdroj: Love Dal\u00e9n\/Stockholm University\n
G\u00e9nom cicavcov je 30-mili\u00f3nkr\u00e1t v\u00e4\u010d\u0161\u00ed ako typick\u00fd fragment starovekej DNA, vysvetlil pre vedeck\u00fd \u010dasopis spoluautor \u0161t\u00fadie Erez Lieberman Aiden, genetik z Baylor College of Medicine v Houstone v\u00a0americkom \u0161t\u00e1te Texas.<\/p>\n
Neporu\u0161en\u00fd chromoz\u00f3m je o \u010dosi jednoduch\u0161\u00ed, ke\u010f\u017ee oproti be\u017en\u00e9mu fragmentu starovekej DNA je dlh\u0161\u00ed len o mili\u00f3nkr\u00e1t. Kv\u00f4li predpokladu, \u017ee 3D \u0161trukt\u00fara DNA \u010dasom zanikne sa doteraz nikto nepok\u00fa\u0161al sk\u00fama\u0165 chromoz\u00f3my v jadr\u00e1ch starovek\u00fdch buniek.<\/p>\n
V\u00fdsledky ich v\u00fdskumu do ve\u013ekej miery z\u00e1visia od spr\u00e1vne vybranej vzorky. Po\u010das piatich rokov testovali desiatky prepar\u00e1tov, k\u00fdm sa dostali k\u00a0nezvy\u010dajne dobre zachovan\u00e9mu mamutovi srstnat\u00e9mu. Toho vykopali na severov\u00fdchode Sib\u00edri v\u00a0roku 2018.<\/p>\n
\u201eMysl\u00edme si, \u017ee spont\u00e1nne zmrzol kr\u00e1tko po svojej smrti,\u201c<\/em> hovor\u00ed spoluautorka \u0161t\u00fadie Olga Dudchenko z Centra pre architekt\u00faru gen\u00f3mu na Baylor College of Medicine. Hovor\u00ed, \u017ee jadrov\u00e1 architekt\u00fara v dehydratovanej vzorke m\u00f4\u017ee pre\u017ei\u0165 neuverite\u013ene dlh\u00fd \u010das.<\/p>\n Na rekon\u0161trukciu gen\u00f3mu mamuta v\u00fdskumn\u00edci extrahovali DNA zo vzorky ko\u017ee odobratej za mamut\u00edm uchom. Pou\u017eili met\u00f3du Hi-C, ktor\u00e1 umo\u017e\u0148uje vedcom odhali\u0165 \u00faseky DNA, ktor\u00e9 sa nach\u00e1dzaj\u00fa bl\u00edzko seba v modern\u00fdch vzork\u00e1ch.<\/p>\n T\u00edm sk\u00famal aj vzorky z mladej samice mamuta, ktor\u00fa objavili v roku 2010. Zdroj: Love Dal\u00e9n\/Stockholm University\n \u201ePredstavte si, \u017ee m\u00e1te sklada\u010dku, ktor\u00e1 m\u00e1 3 miliardy dielikov, ale nem\u00e1te k dispoz\u00edcii obr\u00e1zok fin\u00e1lnej sklada\u010dky,“<\/em> hovor\u00ed spoluautor Marc A. Marti-Renom. Met\u00f3da Hi-C chemicky sp\u00e1ja \u010dasti gen\u00f3mu, \u010d\u00edm poskytuj\u00fa pribli\u017en\u00fa predstavu o tomto \u201eobraze\u201c.<\/p>\n Pomocou jedine\u010dnej upravenej techniky nazvanej PaleoHi-C dok\u00e1zali v\u00fdskumn\u00edci zisti\u0165, \u017ee srstnat\u00e9 mamuty mali 28 p\u00e1rov chromoz\u00f3mov, \u010di\u017ee dokopy mali 56 chromoz\u00f3mov. Rovnak\u00fd po\u010det p\u00e1rov maj\u00fa aj modern\u00e9 slony, uv\u00e1dza port\u00e1l Science.org.<\/p>\n Hoci sme u\u017e vedeli ako srstnat\u00e9 mamuty vyzerali, teraz sa o nich m\u00f4\u017eeme dozvedie\u0165 e\u0161te viac. \u201ePrv\u00fdkr\u00e1t m\u00e1me k dispoz\u00edcii tkanivo mamuta srstnat\u00e9ho, u ktor\u00e9ho pribli\u017ene vieme, ktor\u00e9 g\u00e9ny boli zapnut\u00e9 a ktor\u00e9 vypnut\u00e9,\u201c<\/em> vysvet\u013euje Marti-Renom.<\/p>\n Ako sme u\u017e uviedli, met\u00f3da si vy\u017eaduje nezvy\u010dajne dobre zachovan\u00e9 fos\u00edlie. Vedci s\u00fa v\u0161ak optimistick\u00ed, \u017ee by sa mohla pou\u017ei\u0165 aj na \u0161t\u00fadium in\u00fdch starovek\u00fdch vzoriek DNA, napr\u00edklad u\u017e spom\u00ednan\u00e9 egyptsk\u00e9 m\u00famie, ako aj nov\u0161ie zachovan\u00e9 muze\u00e1lne vzorky.<\/p>\n Port\u00e1l LiveScience uv\u00e1dza, \u017ee porovnan\u00edm novoz\u00edskanej g\u00e9novej aktivity s\u00a0aktivitou slona by vedci mohli ur\u010di\u0165 rozdiely, ktor\u00e9 m\u00f4\u017eu podpori\u0165 prebiehaj\u00face \u00fasilie o\u00a0obnovenie vyhynutej popul\u00e1cie tejto zvery. Vysvetlil to spoluautor \u0161t\u00fadie Juan Antonio Rodr\u00edguez.<\/p>\n T\u00e1to skuto\u010dnos\u0165 v\u0161ak nebola motiv\u00e1ciou \u0161t\u00fadie. \u201eNerobili sme ju \u0161peci\u00e1lne kv\u00f4li snah\u00e1m o rekon\u0161trukciu, ale preto, aby sme sa pou\u010dili z minulosti a z\u00edskali inform\u00e1cie pre bud\u00face rozhodnutia,\u201c<\/em> uviedla Olga Dudchenkov\u00e1.<\/p>\n Napriek tomu Rodr\u00edguez dodal, \u017ee architekt\u00fara gen\u00f3mu \u201eje \u010fal\u0161\u00edm krokom\u201c<\/em> k deextinkcii. Z\u00e1rove\u0148 si mysl\u00ed, \u017ee \u201eexistuje mnoho \u010fal\u0161\u00edch zn\u00e1mych a nezn\u00e1mych krokov, ktor\u00e9 musia vedci vyrie\u0161i\u0165, k\u00fdm mamuta prived\u00fa sp\u00e4\u0165\u201c<\/em> zo z\u00e1hrobia vyhynut\u00fdch \u017eivo\u010d\u00edchov.<\/p>","protected":false},"excerpt":{"rendered":" Ke\u010f za\u010diatkom 90. rokov minul\u00e9ho storo\u010dia pri\u0161iel do k\u00edn film Stevena Spielberga, div\u00e1ci zostali v\u00a0nemom \u00fa\u017ease. Jedna z\u00a0najpam\u00e4tnej\u0161\u00edch sc\u00e9n, ktor\u00e1 zaujala mili\u00f3ny \u013eud\u00ed, vyobrazovala kom\u00e1ra<\/p>","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[51],"tags":[],"class_list":["post-8818","post","type-post","status-publish","format-standard","hentry","category-archiv","two-columns"],"_links":{"self":[{"href":"https:\/\/instrid.sk\/en\/wp-json\/wp\/v2\/posts\/8818","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/instrid.sk\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/instrid.sk\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/instrid.sk\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/instrid.sk\/en\/wp-json\/wp\/v2\/comments?post=8818"}],"version-history":[{"count":0,"href":"https:\/\/instrid.sk\/en\/wp-json\/wp\/v2\/posts\/8818\/revisions"}],"wp:attachment":[{"href":"https:\/\/instrid.sk\/en\/wp-json\/wp\/v2\/media?parent=8818"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/instrid.sk\/en\/wp-json\/wp\/v2\/categories?post=8818"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/instrid.sk\/en\/wp-json\/wp\/v2\/tags?post=8818"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}Stane sa sci-fi realitou?<\/h3>\n