{"id":42662,"date":"2012-12-01T23:36:27","date_gmt":"2012-12-01T21:36:27","guid":{"rendered":"https:\/\/bilimvegelecek.com.tr\/?p=42662"},"modified":"2020-04-18T23:45:44","modified_gmt":"2020-04-18T20:45:44","slug":"rnadan-once-ne-vardi","status":"publish","type":"post","link":"https:\/\/bilimvegelecek.com.tr\/index.php\/2012\/12\/01\/rnadan-once-ne-vardi","title":{"rendered":"RNA\u2019dan \u00f6nce ne vard\u0131?"},"content":{"rendered":"

Haz\u0131rlayan: Rana Fu\u00e7ucuo\u011flu<\/strong><\/p>\n

Biliminsanlar\u0131 d\u00fcnyan\u0131n ba\u015fl\u0131ca genetik materyali olarak DNA\u2019n\u0131n ortaya \u00e7\u0131kmas\u0131ndan \u00f6nce, erken ya\u015fam formlar\u0131n\u0131n genetik bilgileri kodlamak i\u00e7in RNA kulland\u0131\u011f\u0131na inan\u0131yor. Peki ya\u015fam, RNA\u2019dan \u00f6nce ne \u00e7e\u015fit molek\u00fcllere dayan\u0131yordu?<\/p>\n

Cevap AEG olabilir; zincirlere ba\u011fland\u0131\u011f\u0131nda n\u00fckleik asitler i\u00e7in kuramsal bir iskelet olu\u015fturan, ilk genetik molek\u00fcl oldu\u011fu varsay\u0131lan k\u00fc\u00e7\u00fck bir molek\u00fcl. Sentetik AEG, ila\u00e7 end\u00fcstrisi taraf\u0131ndan, belirli genetik hastal\u0131klar\u0131 durduran ya da yava\u015flatan bir gen susturucu aday\u0131 olarak \u00e7al\u0131\u015f\u0131ld\u0131. Teorinin tek sorunlu yan\u0131, do\u011fada AEG\u2019nin \u015fimdiye kadar bilinmiyor olmas\u0131.<\/p>\n

ABD ve \u0130sve\u00e7\u2019ten bir grup biliminsan\u0131 d\u00fcnyadaki en ilkel organizmalar aras\u0131nda oldu\u011fu d\u00fc\u015f\u00fcn\u00fclen siyanobakterilerde AEG varl\u0131\u011f\u0131n\u0131 ke\u015ffettiklerini duyurdular. Siyanobakteriler zaman zaman s\u0131cak yaz aylar\u0131 s\u00fcresince do\u011fal g\u00f6llerin ve baraj g\u00f6llerinin y\u00fczeyinde yosun veya kir tabakas\u0131 olarak a\u00e7\u0131\u011fa \u00e7\u0131kar. Ayr\u0131ca, Yellowstone kapl\u0131calar\u0131ndan Kuzey Kutbu tundralar\u0131na uzanan a\u015f\u0131r\u0131 habitatlara kar\u015f\u0131 toleranslar\u0131 fevkaladedir.<\/p>\n

\"\"
Siyanobakterilerin en \u00e7etin ko\u015fullarda ya\u015fam\u0131n\u0131 s\u00fcrd\u00fcrebilmesi dikkat \u00e7ekici. Yellowstone Ulusal Park\u0131 da bu ya\u015fam alanlar\u0131ndan biri.<\/figcaption><\/figure>\n

PLOS ONE<\/em> dergisinde \u00e7\u0131kan makalenin ortak yazar\u0131 Dr. Paul Alan Cox, \u201cSiyanobakterilerde AEG ke\u015ffetmemiz beklenmeyen bir \u015feydi.\u201d diye a\u00e7\u0131kl\u0131yor. Amerikal\u0131 ekip \u00fcyeleri Jackson Hole\u2019daki Etnot\u0131p Enstit\u00fcs\u00fc\u2019nde bulunuyor ve Ogden-Utah\u2019taki Weber Devlet \u00dcniversitesi\u2019nde ek kadro olarak hizmet veriyor.<\/p>\n

\u201cTasla\u011f\u0131m\u0131z\u0131 haz\u0131rlarken, Stockholm \u00dcniversitesi Analitik Kimya Departman\u0131\u2019ndaki meslekta\u015flar\u0131m\u0131z\u0131n benzer bir ke\u015fif yapm\u0131\u015f olduklar\u0131n\u0131 \u00f6\u011frendik ve onlardan makaleye kat\u0131lmalar\u0131n\u0131 talep ettik.\u201d diyor Cox.<\/p>\n

Biliminsanlar\u0131 siyanobakterilerde AEG \u00fcretiminin ne kadar yayg\u0131n oldu\u011funu belirlemek i\u00e7in Fransa-Paris\u2019te bulunan Pasteur K\u00fclt\u00fcr Koleksiyonu\u2019ndan el de\u011fmemi\u015f siyanobakteriyel k\u00fclt\u00fcrleri analiz etti. Ayr\u0131ca Guam, Japonya, Katar ve Mo\u011folistan\u2019\u0131n Gobi \u00c7\u00f6l\u00fc\u2019nden (son \u00f6rnek, tan\u0131nm\u0131\u015f Wyoming nat\u00fcralisti Derek Craighead taraf\u0131ndan olmak \u00fczere) siyanobakteri \u00f6rnekleri toplad\u0131lar. Hepsinin AEG \u00fcretti\u011fi saptand\u0131.<\/p>\n

Stockholm \u00dcniversitesi Analitik Kimya Departman\u0131\u2019ndan Profes\u00f6r Leopold Ilag ve \u00f6\u011frencisi Liying Jiang ayn\u0131 \u00f6rnekleri analiz etti ve birebir ayn\u0131 sonuca ula\u015ft\u0131: Siyanobakteriler AEG \u00fcretiyor. Analiz kesin oldu\u011fu halde, sonu\u00e7lar\u0131n d\u00fcnyadaki erken ya\u015fam formlar\u0131 \u00e7al\u0131\u015fmalar\u0131 a\u00e7\u0131s\u0131ndan \u00f6nemi belirsiz kalmaya devam ediyor. Siyanobakteriler taraf\u0131ndan AEG \u00fcretilmesi acaba d\u00fcnyadaki ilk ya\u015fam\u0131n bir yank\u0131s\u0131 m\u0131d\u0131r?<\/p>\n

Cox, \u201c\u00d6yle bir sonuca ula\u015fmak i\u00e7in hen\u00fcz yeterli veriye sahip de\u011filiz.\u201d diye bildiriyor. \u201cAncak ila\u00e7 end\u00fcstrisi, gen susturmada kullan\u0131lmaya aday sentetik AEG polimerlerini ara\u015ft\u0131rmakta; bu y\u00fczden san\u0131yorum ki daha \u00f6\u011frenecek \u00e7ok \u015feyimiz var\u201d.<\/p>\n

Kaynak:\u00a0<\/strong>\u201cScientists Discover Possible Building Blocks of Ancient Genetic Systems in Earth’s Most Primitive Organisms\u201d, http:\/\/www.sciencedaily.com\/releases\/2012\/11\/121110093550.htm.<\/p>\n","protected":false},"excerpt":{"rendered":"

Haz\u0131rlayan: Rana Fu\u00e7ucuo\u011flu Biliminsanlar\u0131 d\u00fcnyan\u0131n ba\u015fl\u0131ca genetik materyali olarak DNA\u2019n\u0131n ortaya \u00e7\u0131kmas\u0131ndan \u00f6nce, erken ya\u015fam formlar\u0131n\u0131n genetik bilgileri kodlamak i\u00e7in RNA kulland\u0131\u011f\u0131na inan\u0131yor. Peki ya\u015fam, RNA\u2019dan \u00f6nce ne \u00e7e\u015fit molek\u00fcllere dayan\u0131yordu? Cevap AEG olabilir; zincirlere ba\u011fland\u0131\u011f\u0131nda n\u00fckleik asitler i\u00e7in kuramsal bir iskelet olu\u015fturan, ilk genetik molek\u00fcl oldu\u011fu varsay\u0131lan k\u00fc\u00e7\u00fck bir molek\u00fcl. Sentetik AEG, ila\u00e7 end\u00fcstrisi […]<\/p>\n","protected":false},"author":429,"featured_media":42663,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[143,19,38,231],"tags":[6276,272,292,2055,3977],"class_list":["post-42662","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-106-sayi","category-bilim-gundemi","category-dergi-sayilari","category-molekuler-biyoloji-ve-genetik","tag-aeg","tag-dna","tag-genetik","tag-rna","tag-siyanobakteriler"],"acf":[],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t