{"id":19841,"date":"2006-07-01T12:53:48","date_gmt":"2006-07-01T09:53:48","guid":{"rendered":"https:\/\/bilimvegelecek.com.tr\/?p=19841"},"modified":"2018-02-19T13:05:19","modified_gmt":"2018-02-19T10:05:19","slug":"yasam-kitabinin-ilk-sayfasinda-ne-var-gen-mi-rna-mi","status":"publish","type":"post","link":"https:\/\/bilimvegelecek.com.tr\/index.php\/2006\/07\/01\/yasam-kitabinin-ilk-sayfasinda-ne-var-gen-mi-rna-mi","title":{"rendered":"Ya\u015fam kitab\u0131n\u0131n ilk sayfas\u0131nda ne var?\u00a0Gen mi RNA m\u0131?"},"content":{"rendered":"

Bug\u00fcn giderek a\u00e7\u0131\u011fa \u00e7\u0131k\u0131yor ki, insan ve genel olarak ya\u015fam san\u0131ld\u0131\u011f\u0131ndan da karma\u015f\u0131k. Biyolojik canl\u0131 do\u011fas\u0131 sadece gene indirgenemeyecek denli geli\u015fkin, i\u00e7 i\u00e7e, girift ve kompleks. Say\u0131s\u0131z etken ya\u015fam \u00fczerinde etki yap\u0131p de\u011fi\u015ftiriyor, bir\u00e7ok \u015feyi birbirine d\u00f6n\u00fc\u015ft\u00fcr\u00fcyor. Son bulgular \u00f6ylesine \u00f6nemli ki, molek\u00fcler biyoloji ve genetikte bug\u00fcn bilinenleri temelinden sarsacak. Gen nedir, kal\u0131t\u0131m nedir, kal\u0131t\u0131m birimi nedir bug\u00fcn yeniden sorulmaya ba\u015fland\u0131. Soru soruyu getiriyor. Gen e\u011fer kal\u0131t\u0131m\u0131n en k\u00fc\u00e7\u00fck birimi ve bu anlamda da ya\u015fam\u0131n k\u00f6keni de\u011filse, o zaman bu en k\u00fc\u00e7\u00fck birim ve ya\u015fam\u0131n k\u00f6keni nedir? Yan\u0131tlanmas\u0131 gereken \u00e7ok soru var. <\/span><\/i><\/p>\n

Bir bu\u00e7uk ay kadar \u00f6nce, May\u0131s ay\u0131nda, insan genomunun son halkas\u0131n\u0131n okunmas\u0131 da tamamland\u0131. Bilim d\u00fcnyas\u0131n\u0131n en prestijli dergilerinden Nature<\/i>\u2019da yay\u0131nlanan Uluslararas\u0131 \u0130nsan Genomu Konsorsiyomu\u2019nun makalesinde, insan 1. kromozomunun s\u0131ralanmas\u0131n\u0131n da t\u00fcm\u00fcyle tespit edildi\u011fi duyuruldu. B\u00f6ylece 5,5 y\u0131ld\u0131r s\u00fcrekli tamamland\u0131 denilip durulan insan genomunun s\u0131ralanmas\u0131n\u0131n \u00e7\u0131kar\u0131lmas\u0131, ya da daha basit anlat\u0131mla harf diziliminin tespit edilmesi i\u015flemi bir ay kadar \u00f6nce bitirilmi\u015f oldu. Harf dizilimi \u00e7\u0131kar\u0131lmas\u0131na \u00e7\u0131kar\u0131ld\u0131 ama, bu harfler ve dizilimlerinin ne anlama geldikleri, okunup anlamland\u0131r\u0131lmas\u0131, kesin gen say\u0131s\u0131n\u0131n belirlenmesi yine de birka\u00e7 y\u0131l\u0131 bulacak. K\u0131sacas\u0131, \u015eubat 2001\u2019de, arkas\u0131na Clinton ve Blair deste\u011fini alan medyan\u0131n \u00e7ok b\u00fcy\u00fck sansasyonla okundu\u011funu ilan etti\u011fi, \u201cya\u015fam\u0131n kitab\u0131\u201d h\u00e2l\u00e2 okunmaya devam ediyor. <\/span><\/p>\n

\u0130nsan DNA\u2019s\u0131n\u0131n toplam harf diziliminin, yani genomun belirlenip okunmas\u0131 i\u015flemi s\u00fcrerken, okundu\u011fu y\u0131llar \u00f6nce ilan edilen \u201cya\u015fam\u0131n kitab\u0131\u201dn\u0131n yeni yeni marifetleri ortaya \u00e7\u0131k\u0131yor. \u00d6zellikle son birka\u00e7 y\u0131lda bulunmaya ba\u015flanan yeni bilgi ve bulgular, \u00f6ylesine g\u00f6rkemli, \u00f6ylesine de\u011fi\u015fik ki, molek\u00fcler biyoloji ve genetikte bug\u00fcne dek bilinenlerin \u00e7o\u011funu adeta \u00e7\u00f6pe atacak; geneti\u011fin paradigmalar\u0131n\u0131 neredeyse toptan de\u011fi\u015ftirecek nitelikte. Daha da \u00f6tesi, \u015fimdilik ortaya \u00e7\u0131kar\u0131lan bilgi ve bulgular, \u00e7\u0131kar\u0131lacak olanlar\u0131n hen\u00fcz \u00e7ok k\u00fc\u00e7\u00fck bir k\u0131sm\u0131. Buzda\u011f\u0131n\u0131n \u015fimdilik sadece su \u00fcst\u00fcndeki b\u00f6l\u00fcm\u00fc g\u00f6r\u00fcn\u00fcyor. As\u0131l dev b\u00f6l\u00fcm su alt\u0131nda. Aysbergin alt\u0131nda, belki de geni taht\u0131ndan indirecek, en az\u0131ndan ona bir ortak daha getirecek \u00f6nemde yepyeni bir d\u00fcnya var.<\/span><\/p>\n

\u0130lk gen 1972\u2019de tespit edilip klonland\u0131. \u0130lk genin bulunmas\u0131yla ortal\u0131\u011f\u0131 h\u0131zla bir gen dalgas\u0131 sard\u0131. Bu \u00f6ylesine bir dalgayd\u0131 ki, hemen her \u015fey sadece genlerle a\u00e7\u0131klanmaya ba\u015flad\u0131. Kal\u0131t\u0131m\u0131n en k\u00fc\u00e7\u00fck biriminin gen olmas\u0131 tezinden yola \u00e7\u0131k\u0131larak genler ya\u015famla ilgili her \u015feyi belirleyen, mutlak, de\u011fi\u015ftirilmesi olanaks\u0131z birimler olarak sunuldular. \u0130\u015f iyice \u00e7\u0131\u011f\u0131r\u0131ndan \u00e7\u0131kt\u0131 ve genler sonunda, Kant\u2019\u0131n \u201ckendinde-\u015fey\u201di gibi, insan kaderinin ac\u0131mas\u0131z efendisi yap\u0131l\u0131p \u00e7\u0131kar\u0131ld\u0131lar. Yaln\u0131zca insanla ilgili biyolojik, psi\u015fik, sosyal, ideolojik-k\u00fclt\u00fcrel kategoriler de\u011fil, tek tek her bir durum ve davran\u0131\u015f i\u00e7in ayr\u0131 ayr\u0131 genler bulundu\u011fu \u00f6ne s\u00fcr\u00fcld\u00fc. \u00d6yle ki, inan\u00e7 ya da \u201ctanr\u0131 geni\u201d buldu\u011funu iddia edenler bile oldu. <\/span><\/p>\n

Bu bak\u0131\u015f\u0131n dayanak noktalar\u0131ndan birisi, \u00e7ok uzun y\u0131llard\u0131r h\u00fck\u00fcm s\u00fcren, eski \u201cbir gen bir protein\u201d teziydi. Bu teze g\u00f6re, her gen bir protein ve fonksiyona kar\u015f\u0131l\u0131k geliyordu. \u0130nsanda \u00e7ok say\u0131da fonksiyon oldu\u011funa g\u00f6re \u00e7ok b\u00fcy\u00fck say\u0131larda protein, ve buna ba\u011fl\u0131 olarak bir o kadar da gen bulunmal\u0131yd\u0131. Bu bak\u0131\u015fa g\u00f6re, en geli\u015fkin, en kompleks canl\u0131 t\u00fcr\u00fc olan insan\u0131n gen say\u0131s\u0131 \u00f6teki canl\u0131 t\u00fcrlerinin kat kat fazlas\u0131 olmal\u0131yd\u0131. Kesin rakam bilinmiyordu ama imalar bu rakam\u0131n en az\u0131ndan y\u00fcz binler olmas\u0131 gerekti\u011fine i\u015faret ediyordu. Ara\u015ft\u0131rmalar bu y\u00f6ne yo\u011funla\u015ft\u0131 ve rakamlar gelmeye ba\u015flad\u0131.<\/span><\/p>\n

1997\u2019de bir ABD genom \u015firketi, EST zincirlerine dayanarak yapt\u0131\u011f\u0131 hesaplama sonucunda gen say\u0131s\u0131n\u0131n 140 bin civar\u0131nda oldu\u011funu a\u00e7\u0131klad\u0131. Ba\u015fka bir ara\u015ft\u0131rma kurumu, ABD\u2019deki Center for Biotechnology Information ise rakam\u0131 84 bin olarak belirledi. Bunlardan yola \u00e7\u0131karak rakam\u0131n 100 bin civar\u0131nda oldu\u011fu genel kabul g\u00f6rd\u00fc. Ancak Uluslararas\u0131 \u0130nsan Genomu Konsorsiyomu ve ABD\u2019deki bir ba\u015fka genom \u015firketi Celera, 2001 \u015eubat\u0131nda Nature<\/i> ve Science<\/i> dergilerinde yapt\u0131klar\u0131 a\u00e7\u0131klamalarda b\u00fct\u00fcn tahminleri alt \u00fcst ettiler. Rakam 30-40 bin aras\u0131 \u00e7\u0131km\u0131\u015ft\u0131. Uluslararas\u0131 \u0130nsan Genomu Konsorsiyomu iki sene \u00f6nce, 2004\u2019de, Nature<\/i> dergisinde yay\u0131nlad\u0131\u011f\u0131 bir ba\u015fka \u00e7al\u0131\u015fmas\u0131nda gen say\u0131s\u0131n\u0131 daha da a\u015fa\u011f\u0131 \u00e7ekti. Say\u0131 20-25 bine indi. Son a\u00e7\u0131klamalara g\u00f6re, insan gen say\u0131s\u0131 19 bini tespit edilen ve 2 bin kadar\u0131 da tahmin edilen olmak \u00fczere 21-22 bin civar\u0131nda. Bu yeni durum her \u015feyi alt \u00fcst etti. Ne \u201cbir gen bir protein\u201d tezi kald\u0131, ne de genlerin tanr\u0131l\u0131\u011f\u0131. <\/b><\/span><\/p>\n

Bilindi\u011fi gibi DNA, Adenin, Timin, Guanin ve Sitozin ad\u0131 verilen n\u00fckletid ya da bazlar\u0131n ba\u015fka kimyasal bile\u015fiklerle birle\u015ferek art arda s\u0131ralanmas\u0131ndan olu\u015fmu\u015ftur. Bu bazlar k\u0131saca s\u0131ras\u0131yla A, T, G ve C harfleriyle g\u00f6sterilir. \u0130nsanda b\u00f6yle art arda s\u0131ralanm\u0131\u015f 2 milyar 851 milyon harf (baz) vard\u0131r. <\/span><\/p>\n

\u0130nsan dahil canl\u0131 organizmalardaki fonksiyonlar\u0131n yerine getirilmesinde protein ve enzimler \u00e7ok \u00f6nemli roller \u00fcstlenirler. Bu protein ve enzimler DNA \u00fczerindeki baz\u0131 dizilimlere g\u00f6re kodlan\u0131p \u00fcretilirler. Ancak -\u015fimdiki bilgilerimize g\u00f6re- DNA diziliminin t\u00fcm\u00fc de\u011fil k\u00fc\u00e7\u00fck bir k\u0131sm\u0131 RNA ve protein \u00fcretimine kat\u0131l\u0131r. \u0130\u015fte DNA\u2019n\u0131n, RNA ve protein \u00fcretiminde rol alan belli harf dizilimlerine gen ad\u0131 verilir. Bir protein yap\u0131laca\u011f\u0131 zaman DNA \u00fczerindeki genin harf dizilimi \u00f6rnek al\u0131narak onun benzer bir RNA kopya dizilimi \u00e7\u0131kar\u0131l\u0131r. Kopyalanan RNA mesaj ta\u015f\u0131yan anlam\u0131nda haberci RNA\u2019d\u0131r (mRNA). \u00a0<\/span>mRNA\u2019lar di\u011fer RNA\u2019lar taraf\u0131ndan \u00e7ekirdek d\u0131\u015f\u0131na \u00e7\u0131kar\u0131l\u0131p yine ba\u015fka RNA\u2019lar ve enzimlerin yard\u0131m\u0131yla protein ve kimi enzimlerin kodlanmas\u0131n\u0131 sa\u011flarlar. K\u0131sacas\u0131, DNA\u2019daki genden RNA, RNA\u2019dan da protein yap\u0131l\u0131r. <\/span><\/p>\n

Ancak, mRNA yap\u0131l\u0131rken, DNA \u00fczerindeki genin harf dizilimi ba\u015ftan sona t\u00fcm\u00fcyle okunmaz. Okuma atlana atlana gider. Bir k\u0131s\u0131m dizilim okunup kopyas\u0131 \u00e7\u0131kar\u0131ld\u0131ktan sonra birden uzun bir b\u00f6l\u00fcm okunmadan atlan\u0131p \u00e7ok daha ilerideki bir ba\u015fka b\u00f6l\u00fcme ge\u00e7ilir ve oradan devam edilir. Bir s\u00fcre sonra yine bir b\u00f6l\u00fcm atlan\u0131p bir sonraki b\u00f6l\u00fcme ge\u00e7ilir. Bu b\u00f6ylece devam eder. B\u00f6yle atlaya atlaya, ya da s\u0131\u00e7raya s\u0131\u00e7raya okunmaya molek\u00fcler biyoloji dilinde RNA splincing<\/span><\/b>,<\/i> (RNA s\u0131\u00e7rama ya da atlamas\u0131) denir. DNA\u2019n\u0131n RNA yap\u0131l\u0131rken okunan bu b\u00f6l\u00fcmlerine exon<\/span><\/b>, okunmadan atlanan b\u00f6l\u00fcmlerine ise intron<\/span><\/b> ad\u0131 verilir. \u0130ntronlar atlan\u0131p okunmad\u0131klar\u0131 i\u00e7in mRNA ve protein kodlanmas\u0131na kat\u0131lmazlar. Bu y\u00fczden protein yap\u0131m\u0131n\u0131 kodlayan dizilim, sadece exonlardaki dizilimlerdir. Genler b\u00f6yle exon ve intronlardan olu\u015fmu\u015ftur. (\u015eekil 1)<\/span><\/p>\n

\"\"
\u00a0\u015eekil 1: RNA s\u0131\u00e7ramas\u0131 (RNA splicing)<\/figcaption><\/figure>\n

Genetikte aralanan yeni kap\u0131: RNA<\/span><\/b><\/p>\n

Ancak daha sonra, exonlar\u0131n genin \u00e7ok k\u00fc\u00e7\u00fck bir k\u0131sm\u0131n\u0131 olu\u015fturduklar\u0131, genlerin as\u0131l b\u00fcy\u00fck k\u0131sm\u0131n\u0131 mRNA ve protein yap\u0131m\u0131na kat\u0131lmayan intronlar\u0131n te\u015fkil etti\u011fi g\u00f6r\u00fcld\u00fc. Zaten protein yap\u0131m\u0131na kat\u0131lan genler de insan genomunun d\u00f6rtte birine yak\u0131n\u0131n\u0131 olu\u015fturuyorlard\u0131. Bug\u00fcnk\u00fc bilgilerimize g\u00f6re, protein (ve tabi ki mRNA) kodlanmas\u0131na kat\u0131lan genlerin exon b\u00f6l\u00fcmleri toplam insan genomunun sadece y\u00fczde 1,2\u2019sini meydana getiriyor. Geri kalan y\u00fczde 98,8\u2019lik dev b\u00f6l\u00fcm protein ve mRNA kodlanmas\u0131na kat\u0131lm\u0131yor. Bug\u00fcne dek bu dev b\u00f6l\u00fcm\u00fcn, DNA\u2019n\u0131n bir i\u015fe yaramayan, hi\u00e7bir fonksiyonu olmayan, \u00e7er \u00e7\u00f6p anlam\u0131ndaki \u201cjunk DNA<\/b>\u201d oldu\u011fu s\u00f6yleniyordu. Oysa son birka\u00e7 y\u0131lda aralanmaya ba\u015flanan ve yepyeni bir d\u00fcnyaya a\u00e7\u0131lan kap\u0131 bunun hi\u00e7 de b\u00f6yle olmad\u0131\u011f\u0131n\u0131 g\u00f6steriyor. Son birka\u00e7 y\u0131l\u0131n yepyeni bulgular\u0131, DNA \u00fczerinde, bir i\u015fe yaramad\u0131\u011f\u0131, hi\u00e7bir fonksiyona yol a\u00e7mad\u0131\u011f\u0131 s\u00f6ylenen bu s\u00f6zde fazlal\u0131k-\u00e7er \u00e7\u00f6p (junk) b\u00f6l\u00fcmlerin de kodland\u0131\u011f\u0131n\u0131 g\u00f6steriyor. Protein yap\u0131m\u0131na kat\u0131lmayan intron ve DNA\u2019n\u0131n genlerin d\u0131\u015f\u0131nda kalan b\u00f6l\u00fcmlerinin asl\u0131nda, h\u00fccre ve canl\u0131 ya\u015fam\u0131nda \u00e7ok b\u00fcy\u00fck g\u00f6rev ve fonksiyonlar \u00fcstlendi\u011fi g\u00f6r\u00fcl\u00fcyor. Bu dev b\u00f6l\u00fcm \u00e7ok farkl\u0131 say\u0131 ve \u00e7e\u015fitte, \u00e7ok k\u00fc\u00e7\u00fckten \u00e7ok b\u00fcy\u00fc\u011fe, deyim yerindeyse bin bir \u00e7e\u015fit farkl\u0131 RNA kodluyor. Yeni bulunmaya ba\u015flanan bu RNA\u2019lar, do\u011frudan protein kodlamasalar da, hangi proteinin nerede, nas\u0131l ve ne kadar, ne zaman kodlanaca\u011f\u0131n\u0131; ne zaman durdurulup ne zaman ba\u015flat\u0131laca\u011f\u0131n\u0131; hangi genin hangi genle, ya da hangi proteinin hangi proteinle birle\u015ftirilece\u011fini; nereden nereye g\u00f6t\u00fcr\u00fclece\u011fini; hangi h\u00fccre ve dokunun hangi organda ne kadar ve ne zaman yap\u0131laca\u011f\u0131n\u0131; b\u00fcy\u00fcme ve geli\u015fmenin nerede nas\u0131l d\u00fczenlenece\u011fini; k\u00f6k h\u00fccrelerin nerede hangi h\u00fccre, doku ve organlara d\u00f6n\u00fc\u015fece\u011fini; hangi genin hangi ko\u015fullarda susturulup \u00e7al\u0131\u015ft\u0131r\u0131lmayaca\u011f\u0131n\u0131 ya da daha \u00f6nce sessiz kal\u0131p fonksiyon g\u00f6stermeyen hangi genin hangi ko\u015fullarda yeniden \u00e7al\u0131\u015fmaya ba\u015flat\u0131laca\u011f\u0131n\u0131; bir gen okunurken hangi b\u00f6l\u00fcm\u00fcn okunup hangi b\u00f6l\u00fcm\u00fcn okunmayaca\u011f\u0131n\u0131, ne zaman, nereden nereye atlanaca\u011f\u0131n\u0131; h\u00fccrelerin hangi ko\u015fullarda \u00e7o\u011falt\u0131l\u0131p ya da \u00f6ld\u00fcr\u00fclece\u011fini, ne zaman kanser geli\u015ftirilece\u011fini, h\u00fccre \u00e7o\u011falma ve b\u00f6l\u00fcnmesini, kromozomlar\u0131n yap\u0131s\u0131n\u0131, k\u0131sacas\u0131 canl\u0131n\u0131n biyolojik ya\u015fam\u0131n\u0131n neredeyse t\u00fcm\u00fcn\u00fc, nas\u0131l d\u00fczenlenece\u011fini ba\u015ftan sona sa\u011fl\u0131yorlar. \u00d6yle g\u00f6r\u00fcn\u00fcyor ki, neyin nas\u0131l olaca\u011f\u0131n\u0131 belirleyen genler de\u011fil, as\u0131l olarak bu \u00e7ok k\u00fc\u00e7\u00fck RNA par\u00e7ac\u0131klar\u0131. \u00a0<\/span><\/span><\/p>\n

Tablo 1 de\u011fi\u015fik canl\u0131 t\u00fcrlerinin genom b\u00fcy\u00fckl\u00fcklerini yani DNA\u2019daki harf say\u0131lar\u0131n\u0131, gen say\u0131s\u0131 ve protein kodlayan ve kodlamayan RNA miktar ve oranlar\u0131n\u0131 g\u00f6steriyor. Tablodan da g\u00f6r\u00fclece\u011fi gibi, sadece bug\u00fcnk\u00fc en son bilgilere g\u00f6re, insanda DNA\u2019n\u0131n protein kodlayan gen b\u00f6l\u00fcmleri b\u00fct\u00fcn DNA\u2019n\u0131n sadece 1,2\u2019sini olu\u015ftururken protein kodlamas\u0131 yapmayan RNA (non-coding \u2013 ncRNA) b\u00fct\u00fcn DNA\u2019n\u0131n -bug\u00fcn bilindi\u011fi kadar\u0131yla- y\u00fczde 57\u2019sini olu\u015fturuyor. Bu oran, farede y\u00fczde 1,3 ve y\u00fczde 54. Kodlama yapan b\u00f6l\u00fcmler meyve sine\u011finde y\u00fczde 18, solucanda ise 26. DNA\u2019n\u0131n protein kodlamas\u0131 yapmayan k\u00fc\u00e7\u00fck RNA (ncRNA) kodlayan b\u00f6l\u00fcmlerinin protein kodlamas\u0131 yapan b\u00f6l\u00fcmlerine oran\u0131 insanda 47\u2019ye 1 iken bu oran farede 43\u2019e 1, meyve sine\u011finde yakla\u015f\u0131k 2,5\u2019a 1, solucanda neredeyse 1\u2019e 1. <\/span><\/p>\n\n\n\n\n\n\n\n\n
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Organizma (T\u00fcr)<\/span><\/b><\/p>\n<\/td>\n

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Gen say\u0131s\u0131 <\/span><\/b><\/p>\n<\/td>\n

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Genom b\u00fcy\u00fckl\u00fc\u011f\u00fc (toplam baz\u00a0 <\/span><\/span>\/ harf<\/span><\/b> say\u0131s\u0131)<\/span><\/b><\/p>\n<\/td>\n

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Protein ve mRNA kodlayan baz say\u0131s\u0131<\/span><\/b><\/p>\n<\/td>\n

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Protein kodlamad\u0131\u011f\u0131 halde ncRNA kodlayan baz say\u0131s\u0131<\/span><\/b><\/p>\n<\/td>\n

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Protein kodlamayan RNA\u2019n\u0131n protein kodlayan RNA\u2019ya oran\u0131<\/span><\/b><\/p>\n<\/td>\n<\/tr>\n

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(Bin)<\/span><\/p>\n<\/td>\n

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Milyon (Mb)<\/span><\/p>\n<\/td>\n

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Milyon (Mb)<\/span><\/p>\n<\/td>\n

\n

Genoma g\u00f6re oran\u0131 (%)<\/span><\/p>\n<\/td>\n

\n

Milyon (Mb)<\/span><\/p>\n<\/td>\n

\n

Genoma g\u00f6re oran\u0131 (%)<\/span><\/p>\n<\/td>\n<\/tr>\n

\n

\u0130nsan<\/span><\/b><\/p>\n<\/td>\n

\n

20-25<\/span><\/p>\n<\/td>\n

\n

2 851<\/span><\/p>\n<\/td>\n

\n

34<\/span><\/p>\n<\/td>\n

\n

1,2<\/span><\/p>\n<\/td>\n

\n

1619<\/span><\/p>\n<\/td>\n

\n

57<\/span><\/p>\n<\/td>\n

\n

47 <\/span>\/ <\/span>1<\/span><\/p>\n<\/td>\n<\/tr>\n

\n

Fare<\/span><\/b><\/p>\n<\/td>\n

\n

20-25<\/span><\/p>\n<\/td>\n

\n

2 490<\/span><\/p>\n<\/td>\n

\n

31<\/span><\/p>\n<\/td>\n

\n

1,3<\/span><\/p>\n<\/td>\n

\n

1339<\/span><\/p>\n<\/td>\n

\n

54<\/span><\/p>\n<\/td>\n

\n

43 <\/span>\/ <\/span>1<\/span><\/p>\n<\/td>\n<\/tr>\n

\n

Meyve sine\u011fi<\/span><\/b><\/p>\n<\/td>\n

\n

13,6<\/span><\/p>\n<\/td>\n

\n

120<\/span><\/p>\n<\/td>\n

\n

22<\/span><\/p>\n<\/td>\n

\n

18<\/span><\/p>\n<\/td>\n

\n

53<\/span><\/p>\n<\/td>\n

\n

44<\/span><\/p>\n<\/td>\n

\n

2.4 <\/span>\/ <\/span>1<\/span><\/p>\n<\/td>\n<\/tr>\n

\n

Solucan<\/span><\/b><\/p>\n<\/td>\n

\n

19<\/span><\/p>\n<\/td>\n

\n

100<\/span><\/p>\n<\/td>\n

\n

26<\/span><\/p>\n<\/td>\n

\n

26<\/span><\/p>\n<\/td>\n

\n

33<\/span><\/p>\n<\/td>\n

\n

33<\/span><\/p>\n<\/td>\n

\n

1.3 <\/span>\/ <\/span>1<\/span><\/p>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Tablo 1: Baz\u0131 canl\u0131 t\u00fcrlerinde genom b\u00fcy\u00fckl\u00fc\u011f\u00fc, gen say\u0131s\u0131, ve protein kodlayan ve kodlamayan RNA oran\u0131. (Kaynak: Frith et al, (2005), European Journal of Human Genetics<\/i>, 13: 894-897) <\/span><\/p>\n

G\u00f6r\u00fcld\u00fc\u011f\u00fc gibi canl\u0131 t\u00fcr\u00fc ne kadar geli\u015fkin ve kompleks olursa kodlama yapmayan k\u00fc\u00e7\u00fck RNA (ncRNA) say\u0131s\u0131 da o kadar fazla oluyor. Daha basit canl\u0131lar\u0131n daha az protein kodlamayan RNA\u2019s\u0131 (ncRNA), daha geli\u015fkin canl\u0131lar\u0131nsa daha fazla kodlama yapmayan ncRNA\u2019s\u0131 var. \u00d6rne\u011fin en basit canl\u0131 t\u00fcrlerinden bakteri gibi \u00e7ekirdek i\u00e7ermeyen prokaryot t\u00fcrlerinde intron ve buna ba\u011fl\u0131 olarak kodlama yapmayan ncRNA ya yok ya da \u00e7ok az. Bu y\u00fczden genellikle daha basit canl\u0131 t\u00fcrlerinin genomlar\u0131 en geli\u015fkin t\u00fcr olan insan\u0131n genomundan (toplam DNA\u2019dan) daha b\u00fcy\u00fck. Tablo 2\u2019den g\u00f6r\u00fclece\u011fi gibi, \u00f6rne\u011fin en basit canl\u0131lardan bir amip t\u00fcr\u00fc olan Amoeba dubia<\/span><\/em>\u2019n\u0131n genom b\u00fcy\u00fckl\u00fc\u011f\u00fc insan\u0131n 235 kat\u0131. \u0130nsan genomu 2,8 Mb, yani insan DNA\u2019s\u0131ndaki harf say\u0131s\u0131 2 milyar 852 milyon iken, bu say\u0131 <\/span>Amoeba dubia<\/span><\/em>\u2019da 670 milyar. Ayn\u0131 say\u0131 bir ba\u015fka amip t\u00fcr\u00fcnde 290 milyar, bir kurba\u011fa t\u00fcr\u00fcnde ise 6,9 milyar. Tekrar hat\u0131rlatal\u0131m, bu say\u0131 insanda 2,8 milyar. \u0130nsandaki kodlama yapmayan RNA \u00e7oklu\u011fu, o<\/span><\/em> kadar geli\u015fkin olmas\u0131na kar\u015f\u0131n insanda neden sadece 20 bin civar\u0131nda gen oldu\u011funu; neden \u00e7ok daha az geli\u015fkin olan fare ve hatta solucanla neredeyse ayn\u0131 say\u0131da gen bulundu\u011funu a\u00e7\u0131klar gibi. <\/span><\/p>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
\n

Organizma (T\u00fcr)<\/span><\/b><\/p>\n<\/td>\n

\n

Genom b\u00fcy\u00fckl\u00fc\u011f\u00fc (toplam baz <\/span>\/ harf<\/span><\/b> say\u0131s\u0131)<\/span><\/b><\/p>\n<\/td>\n<\/tr>\n

\n

Milyon (Mb)<\/span><\/p>\n<\/td>\n<\/tr>\n

\n

Amoeba dubia (<\/b><\/span><\/em>bir amip t\u00fcr\u00fc)<\/span><\/b><\/em><\/b><\/p>\n<\/td>\n

\n

670 000<\/span><\/p>\n<\/td>\n<\/tr>\n

\n

Amoeba proteus <\/span><\/em>(bir amip t\u00fcr\u00fc)<\/span><\/b><\/em><\/i><\/b><\/p>\n<\/td>\n

\n

290 000<\/span><\/p>\n<\/td>\n<\/tr>\n

\n

Bufo bufo <\/span><\/em>(bir kurba\u011fa t\u00fcr\u00fc)<\/span><\/b><\/em><\/b><\/p>\n<\/td>\n

\n

6 900<\/span><\/p>\n<\/td>\n<\/tr>\n

\n

\u0130nsan<\/span><\/b><\/p>\n<\/td>\n

\n

2 851<\/span><\/p>\n<\/td>\n<\/tr>\n

\n

Fare<\/span><\/b><\/p>\n<\/td>\n

\n

2 490<\/span><\/p>\n<\/td>\n<\/tr>\n

\n

Boa constrictor <\/span><\/i>(Bo\u011fa y\u0131lan\u0131)<\/span><\/b><\/b><\/p>\n<\/td>\n

\n

2 100<\/span><\/p>\n<\/td>\n<\/tr>\n

\n

Rhinolophus ferrumequinum <\/span><\/em>(Yarasa)<\/span><\/b><\/em><\/i><\/b><\/p>\n<\/td>\n

\n

1 929<\/span><\/p>\n<\/td>\n<\/tr>\n

\n

Arabidopsis thaliana <\/b><\/span><\/em>(bir \u00e7i\u00e7ek)<\/span><\/b><\/em><\/b><\/p>\n<\/td>\n

\n

125<\/span><\/p>\n<\/td>\n<\/tr>\n

\n

Meyve sine\u011fi<\/span><\/b><\/p>\n<\/td>\n

\n

120<\/span><\/p>\n<\/td>\n<\/tr>\n

\n

Solucan<\/span><\/b><\/p>\n<\/td>\n

\n

100<\/span><\/p>\n<\/td>\n<\/tr>\n

\n

Hamur mayas\u0131<\/span><\/b><\/p>\n<\/td>\n

\n

12<\/span><\/p>\n<\/td>\n<\/tr>\n

\n

E. Coli (<\/b><\/span><\/i>bir bakteri)<\/span><\/b><\/p>\n<\/td>\n

\n

4,1<\/span><\/p>\n<\/td>\n<\/tr>\n

\n

HIV 1 vir\u00fcs\u00fc<\/span><\/b><\/b><\/p>\n<\/td>\n

\n

0,019<\/span><\/p>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Tablo 2: Baz\u0131 canl\u0131 t\u00fclerinin genom b\u00fcy\u00fckl\u00fckleri (DNA\u2019daki harf say\u0131s\u0131). Kaynak: Database of Genome Sizes, Center for Biological Squence Analysis. <\/span><\/p>\n

Bir genin binlerce farkl\u0131 formu var<\/span><\/b><\/p>\n

1977\u2019de exon ve intronlar\u0131n bulunmas\u0131ndan bir s\u00fcre sonra ama esas olarak son 7-8 y\u0131lda, genlerin bir ba\u015fka \u00f6zelli\u011fi daha tespit edildi. Baz\u0131 genler farkl\u0131 durumlarda farkl\u0131 bi\u00e7imlerde okunuyorlar. Farkl\u0131 durumlarda, \u00f6zellikle de farkl\u0131 \u00e7evresel ko\u015fullarda yaln\u0131zca intronlar de\u011fil, exonlar\u0131n da bir k\u0131sm\u0131 okunmadan atlan\u0131yor. Yani RNA ve oradan da protein yap\u0131laca\u011f\u0131 zaman gen okunurken, baz\u0131 durumlarda bir genin b\u00fct\u00fcn exonlar\u0131 s\u0131ras\u0131yla okunup kopyas\u0131 \u00e7\u0131kar\u0131lm\u0131yor. Bir exonun sadece bir k\u0131sm\u0131 okunup hemen bir ba\u015fka yerine atlan\u0131yor; oradan bir ba\u015fka exonun bir ba\u015fka b\u00f6l\u00fcm\u00fcne ge\u00e7iliyor. Baz\u0131 durumlarda birka\u00e7 exon birden normal bi\u00e7imde s\u0131ras\u0131yla okunduktan sonra birden atlama ba\u015flayarak bir ba\u015fka exonun bir ba\u015fka yerine, oradan ba\u015fka exonlara ya da exonlar\u0131n b\u00f6l\u00fcmlerine ge\u00e7iliyor; baz\u0131 durumlarda da ya bir exonun bir b\u00f6l\u00fcm\u00fc, ya da bir ya da birden fazla exonun tamam\u0131 okunmadan ilerideki bir b\u00f6l\u00fcme atlan\u0131yor. B\u00f6ylece ortaya gendeki as\u0131l dizilimden tamamen farkl\u0131, daha k\u0131sa, daha k\u00fc\u00e7\u00fck ba\u015fka dizilimler \u00e7\u0131k\u0131yor ve sonu\u00e7ta bu farkl\u0131 dizilimlerle bamba\u015fka fonksiyonlara yol a\u00e7an bamba\u015fka proteinler yapacak farkl\u0131 RNA\u2019lar olu\u015fturuluyor. Gen ayn\u0131 olmas\u0131na kar\u015f\u0131n o genin \u00e7ok say\u0131da farkl\u0131 RNA ve proteini ortaya \u00e7\u0131k\u0131yor ve sonu\u00e7ta bir tek genin farkl\u0131 farkl\u0131 varyasyonlar\u0131 olmu\u015f oluyor. Buna alternatif s\u0131\u00e7rama (alternative splicing)<\/span> deniliyor. <\/span><\/p>\n

Bug\u00fcn art\u0131k, genlerin \u00e7ok b\u00fcy\u00fck bir k\u0131sm\u0131n\u0131n b\u00f6yle alternatif atlama ya da s\u0131\u00e7ramalar yapt\u0131\u011f\u0131 biliniyor. Ancak genin hangi ko\u015fulda ne zaman nereye, ya da ne kadar atlayaca\u011f\u0131; hangi ko\u015fulda hangi fonksiyona yol a\u00e7acak hangi protein formunun yap\u0131laca\u011f\u0131n\u0131 belirleyen ve d\u00fczenleyenlerin ne oldu\u011fu bilinmiyordu. Son y\u0131llarda ortaya \u00e7\u0131kt\u0131 ki, bunlar\u0131 sa\u011flayanlar s\u00f6z\u00fcn\u00fc etti\u011fimiz bu k\u00fc\u00e7\u00fck kodlama yapmayan ncRNA par\u00e7ac\u0131klar\u0131. <\/span><\/p>\n

Konuyu daha anla\u015f\u0131l\u0131r k\u0131lmak i\u00e7in basit bir mekanik \u00f6rnek verelim: Bir anahtarc\u0131 d\u00fckk\u00e2n\u0131n\u0131 g\u00f6z \u00f6n\u00fcne getirelim. D\u00fckk\u00e2nda \u00e7ok say\u0131da anahtar as\u0131l\u0131d\u0131r. Ama o anahtarlar tek ba\u015f\u0131na kap\u0131n\u0131n a\u00e7\u0131lmas\u0131n\u0131 sa\u011flamazlar. Bir kap\u0131 a\u00e7\u0131laca\u011f\u0131 zaman, hangi anahtar\u0131n o kap\u0131y\u0131 a\u00e7aca\u011f\u0131n\u0131 bilen birinin d\u00fckk\u00e2ndaki binlerce anahtar aras\u0131ndan en uygununu se\u00e7erek gidip kap\u0131y\u0131 a\u00e7mas\u0131 gerekir. Bu ki\u015fi ayn\u0131 zamanda, o kap\u0131n\u0131n ne zaman a\u00e7\u0131l\u0131p ne zaman kilitlenece\u011fini ve hatta d\u00fckkanda kilide uygun anahtar yoksa, o kilide uygun yeni anahtar yapmas\u0131n\u0131 da bilen usta bir anahtarc\u0131 olmal\u0131d\u0131r. Bug\u00fcn giderek daha net a\u00e7\u0131\u011fa \u00e7\u0131k\u0131yor ki, DNA d\u00fckk\u00e2n\u0131nda as\u0131l\u0131 duran binlerce anahtar (gen) aras\u0131ndan en uygununu se\u00e7ip uygun bi\u00e7imde kilide sokup kap\u0131y\u0131 a\u00e7an (protein yap\u0131m\u0131n\u0131 sa\u011flayan), hatta gerekti\u011finde yeni anahtarlar (genler) yapan bu becerikli ki\u015fi \u00e7ok k\u00fc\u00e7\u00fck boyutlu RNA par\u00e7ac\u0131klar\u0131; yani micro RNA\u2019lar (miRNA), k\u00fc\u00e7\u00fck engelleyici RNA\u2019lar (siRNA), k\u00fc\u00e7\u00fck n\u00fckleer RNA\u2019lar, (snRNA), k\u00fc\u00e7\u00fck n\u00fckleolar RNA\u2019lar (snoRNA), araya giren RNA\u2019lar (RNAi), oligo RNA\u2019lar, genin t\u00fcm\u00fcn\u00fc ya da bir b\u00f6l\u00fcm\u00fcn\u00fc kapatan anti-sense RNA\u2019lar, ikili hatta \u00fc\u00e7l\u00fc sarmal RNA\u2019lar, bir kromozomdaki geni bir ba\u015fka kromozomdaki genle ya da bir ya da birka\u00e7 proteini birle\u015ftirerek daha b\u00fcy\u00fck daha geli\u015fkin proteinler yapan RNA\u2019lar gibi \u00e7ok say\u0131 ve t\u00fcrde k\u00fc\u00e7\u00fck RNA par\u00e7ac\u0131klar\u0131d\u0131r.<\/span><\/p>\n

Gen kavram\u0131 de\u011fi\u015fiyor mu? <\/span><\/b><\/p>\n

Genlerin bulunmas\u0131ndan bu yana en k\u00fc\u00e7\u00fck kal\u0131t\u0131m birimi olarak gen kabul edilir. Bu art\u0131k genel kabuld\u00fcr. Bu genel kabule g\u00f6re, kal\u0131t\u0131m, DNA \u00fczerindeki genler arac\u0131l\u0131\u011f\u0131yla ku\u015faktan ku\u015fa\u011fa aktar\u0131l\u0131r. Klasik geneti\u011fin \u00e7ok uzun y\u0131llard\u0131r h\u00fck\u00fcm s\u00fcren ana ya da merkezi dogmas\u0131na (central dogma) g\u00f6re, kal\u0131tsal bilgi sadece DNA ve onun genleriyle aktar\u0131l\u0131r. DNA\u2019dan RNA, RNA\u2019dan da protein yap\u0131l\u0131r. As\u0131l belirleyici olan DNA\u2019d\u0131r, RNA protein yap\u0131m\u0131nda ara a\u015famad\u0131r ve gidi\u015f y\u00f6n\u00fc her zaman \u201cDNA-RNA-Protein\u201d y\u00f6n\u00fcndedir; bu tersine \u00e7evrilemez. Oysa, uzun s\u00fcredir, retrovirus s\u0131n\u0131f\u0131 baz\u0131 vir\u00fcslerde DNA olmad\u0131\u011f\u0131, sadece RNA bulundu\u011fu biliniyor. Daha da \u00f6tesi bu vir\u00fcslerin RNA\u2019lar\u0131n\u0131 DNA\u2019ya aktard\u0131\u011f\u0131 da bir ger\u00e7ek. Retrovir\u00fcslerin bu \u00f6zelli\u011finden yola \u00e7\u0131karak, bug\u00fcn laboratuvarda, mRNA\u2019lardan DNA kodlan\u0131yor. Molek\u00fcler biyolojinin yayg\u0131n ve en g\u00fcvenilir tekniklerinden RT-PCR\u2019de gidi\u015f DNA\u2019dan RNA\u2019ya de\u011fil, aksine RNA\u2019dan DNA\u2019yad\u0131r. Molek\u00fcler biyoloji ve geneti\u011fin bu merkezi dogmas\u0131 RNA vir\u00fcslerinin bulunmas\u0131ndan sonra \u00e7\u00f6kmesine ra\u011fmen, h\u00e2l\u00e2 genetik bilginin gidi\u015finin DNA\u2019dan RNA ve proteine do\u011fru oldu\u011fu savunuluyordu. Ancak bir bu\u00e7uk ay \u00f6nce ortaya \u00e7\u0131kan yeni bilgiler bu g\u00f6r\u00fc\u015f\u00fcn de k\u0131sa zamanda \u00e7\u00f6pe at\u0131lma olas\u0131l\u0131\u011f\u0131n\u0131n bulundu\u011funu g\u00f6sterdi. <\/span><\/p>\n

Ge\u00e7ti\u011fimiz May\u0131s ay\u0131nda yine Nature<\/i> dergisinde yay\u0131nlanan bir makale, kal\u0131tsal bilgiler ku\u015faktan ku\u015fa\u011fa ge\u00e7erken Mendel yasalar\u0131na ters \u015feylerin oldu\u011funu a\u00e7\u0131\u011fa koydu. Yeni bilgiye g\u00f6re, genlerde olmayan baz\u0131 \u00f6zellikler de yeni ku\u015faklara aktar\u0131l\u0131yor. DNA ya da daha \u00f6zelde genlerde olmayan bir kal\u0131tsal bilgi DNA de\u011fil RNA yoluyla da yeni ku\u015faklara ge\u00e7iriliyor. Kal\u0131tsal bilginin sadece genler de\u011fil ayn\u0131 zamanda RNA yoluyla da aktar\u0131ld\u0131\u011f\u0131 bir s\u00fcre \u00f6nce baz\u0131 bitki t\u00fcrlerinde g\u00f6sterilmi\u015fti. Ancak bunun sadece baz\u0131 bitki t\u00fcrleriyle s\u0131n\u0131rl\u0131 oldu\u011fu san\u0131l\u0131yordu. Oysa Nature<\/i> dergisinde yay\u0131nlanan makale bu \u00f6zelli\u011fin hayvanlarda da (farelerde) oldu\u011funu g\u00f6steriyor. Fransa\u2019dan Minoo Rassoulzadegan ve arkada\u015flar\u0131 yapt\u0131klar\u0131 \u00e7al\u0131\u015fmada, farelerde beyaz kuyruk olu\u015fmas\u0131n\u0131 sa\u011flayan Kit<\/i> geni mutasyonunu ku\u015faklar boyunca \u00fcreme yapt\u0131rarak sonraki ku\u015faklarda d\u00fczeltmi\u015fler. Art\u0131k Kit<\/i> mutasyonu ve bozuk geni bulunmayan ve genetik olarak sa\u011flam olan fareleri birle\u015ftirmi\u015fler. Genetik yap\u0131lar\u0131nda beyaz kuyruk olu\u015fturacak bilgi olmayan yavrularda ola\u011fan renkte kuyruk beklenirken, onlar\u0131n da kuyruklar\u0131 \u015fa\u015f\u0131rt\u0131c\u0131 bi\u00e7imde yine beyaz olmu\u015f. Genetik ve gen yap\u0131lar\u0131 incelendi\u011finde beyaz kuyruk yapan bilginin art\u0131k genlerde olmad\u0131\u011f\u0131; beyaz kuyruk olu\u015fumunu sa\u011flayan bilginin RNA\u2019lar arac\u0131l\u0131\u011f\u0131yla aktar\u0131ld\u0131\u011f\u0131 tespit edilmi\u015f. K\u0131sacas\u0131, gen mutasyonlar\u0131n\u0131n yan\u0131 s\u0131ra RNA\u2019lar yoluyla ge\u00e7en paramutasyonlar\u0131n da oldu\u011fu bulunmu\u015f. Bu k\u00fc\u00e7\u00fck ama genetikteki paradigmalar\u0131 k\u00f6k\u00fcnden sars\u0131p b\u00fct\u00fcn bilgilerin de\u011fi\u015fmesini getirecek bilgi son 1-2 ayd\u0131r genetik\u00e7ilerin akl\u0131n\u0131 ba\u015f\u0131ndan al\u0131yor. \u015eimdi bir\u00e7ok molek\u00fcler biyolog ve genetik\u00e7i, gen ve kal\u0131t\u0131m tan\u0131m\u0131n\u0131n yeniden yap\u0131lmas\u0131 gerekti\u011fini s\u00f6yl\u00fcyor. <\/span><\/p>\n

Harvard \u00dcniversitesi\u2019nden Rick Young, Nature<\/i> dergisinde yer alan bir makalede, bundan 20 y\u0131l kadar \u00f6nce, gen konusunu \u00f6\u011frencilere 2 saatte anlatt\u0131\u011f\u0131n\u0131, oysa \u015fimdi, geni anlatmas\u0131n\u0131n 3 ay\u0131n\u0131 ald\u0131\u011f\u0131n\u0131 s\u00f6yl\u00fcyor. Yeni ortaya \u00e7\u0131kmaya ba\u015flayan bilgilerin ard\u0131ndan, \u00f6yle g\u00f6r\u00fcn\u00fcyor ki, Young\u2019\u0131n gen konusunu anlatmas\u0131 i\u00e7in de\u011fil \u00fc\u00e7, art\u0131k alt\u0131 ay bile yetmeyecek. Daha da \u00f6tesi Young derslerini yeniden haz\u0131rlamak, \u00f6\u011frencilerine \u201ceski bilgilerinizi unutun\u201d demek zorunda kalacak. <\/span><\/p>\n

DNA\u2019dan \u00f6nce RNA vard\u0131<\/span><\/b><\/p>\n

Ya\u015fam\u0131n k\u00f6keninin ne oldu\u011fu, ya\u015fam\u0131n nas\u0131l ortaya \u00e7\u0131kt\u0131\u011f\u0131 sorusu \u00e7ok uzun y\u0131llard\u0131r insan\u0131 me\u015fgul ediyor. Aristo\u2019dan Pasteur\u2019e, Darwin\u2019den, Oparin\u2019e b\u00fcy\u00fck d\u00fc\u015f\u00fcn\u00fcr ve bilim insanlar\u0131 hep bu sorunun yan\u0131tlar\u0131n\u0131 arad\u0131lar. G\u00fcn\u00fcm\u00fczde ya\u015fam\u0131n k\u00f6kenini a\u00e7\u0131klamaya \u00e7al\u0131\u015fan \u00e7ok say\u0131da farkl\u0131 tez ve teori var. Bug\u00fcn kimilerine g\u00f6re, ya\u015fam \u00f6nce basit k\u00fc\u00e7\u00fck amino asitlerler (monomer), kimine g\u00f6re basit ya\u011f-lipid\u2019lerle, kimine g\u00f6re basit enzimler, kimilerine g\u00f6re de basit RNA ve ribozom benzeri yap\u0131lar\u0131n olu\u015fumuyla ba\u015flad\u0131. Bu tez ya da teoriler ne kadar farkl\u0131 olsalar da, asl\u0131nda t\u00fcm\u00fcn\u00fcn bir ortak yan\u0131 var: DNA\u2019dan \u00f6nce RNA vard\u0131 ve bu y\u00fczden de genetik ya da kal\u0131tsal bilgi DNA\u2019dan \u00f6nce RNA ile aktar\u0131l\u0131yordu. <\/span><\/p>\n

Bug\u00fcn giderek a\u00e7\u0131\u011fa \u00e7\u0131k\u0131yor ki, insan ve genel olarak ya\u015fam san\u0131ld\u0131\u011f\u0131ndan da karma\u015f\u0131k. Biyolojik canl\u0131 do\u011fas\u0131 sadece gene indirgenemeyecek denli geli\u015fkin, i\u00e7 i\u00e7e, girift ve kompleks. Say\u0131s\u0131z etken ya\u015fam \u00fczerinde etki yap\u0131p de\u011fi\u015ftiriyor, bir\u00e7ok \u015feyi birbirine d\u00f6n\u00fc\u015ft\u00fcr\u00fcyor. A\u00e7\u0131k ki, t\u00fcm do\u011fay\u0131 oldu\u011fu gibi ya\u015fam\u0131 da diyalekti\u011fin yasalar\u0131 belirliyor. Son bulgular \u00f6ylesine \u00f6nemli, \u00f6ylesine g\u00f6rkemli ki, molek\u00fcler biyoloji ve genetikte bug\u00fcn bilinenleri temelinden sarsacak nitelikte. Bu y\u00fczden genelde ya\u015fam bilimleri ve biyoloji, \u00f6zelde de molek\u00fcler biyoloji ve genetik \u00f6\u011frencileri eski bilgilerini unutmaya haz\u0131rlans\u0131nlar. Yeni bilgiler geliyor. Gen nedir, kal\u0131t\u0131m nedir, kal\u0131t\u0131m birimi nedir bug\u00fcn yeniden sorulmaya ba\u015fland\u0131. Soru soruyu getiriyor. Gen e\u011fer kal\u0131t\u0131m\u0131n en k\u00fc\u00e7\u00fck birimi ve bu anlamda da ya\u015fam\u0131n k\u00f6keni de\u011filse, o zaman bu en k\u00fc\u00e7\u00fck birim ve ya\u015fam\u0131n k\u00f6keni nedir? Yan\u0131tlanmas\u0131 gereken \u00e7ok soru var.<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"

Bug\u00fcn giderek a\u00e7\u0131\u011fa \u00e7\u0131k\u0131yor ki, insan ve genel olarak ya\u015fam san\u0131ld\u0131\u011f\u0131ndan da karma\u015f\u0131k. Biyolojik canl\u0131 do\u011fas\u0131 sadece gene indirgenemeyecek denli geli\u015fkin, i\u00e7 i\u00e7e, girift ve kompleks. Say\u0131s\u0131z etken ya\u015fam \u00fczerinde etki yap\u0131p de\u011fi\u015ftiriyor, bir\u00e7ok \u015feyi birbirine d\u00f6n\u00fc\u015ft\u00fcr\u00fcyor. Son bulgular \u00f6ylesine \u00f6nemli ki, molek\u00fcler biyoloji ve genetikte bug\u00fcn bilinenleri temelinden sarsacak. Gen nedir, kal\u0131t\u0131m nedir, kal\u0131t\u0131m […]<\/p>\n","protected":false},"author":473,"featured_media":19843,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[67,21,1464,231],"tags":[197,272,431,292,2055,595],"class_list":["post-19841","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-29-sayi","category-biyoloji","category-dosya","category-molekuler-biyoloji-ve-genetik","tag-biyoloji","tag-dna","tag-gen","tag-genetik","tag-rna","tag-yasam"],"acf":[],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/posts\/19841","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/users\/473"}],"replies":[{"embeddable":true,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/comments?post=19841"}],"version-history":[{"count":0,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/posts\/19841\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/media\/19843"}],"wp:attachment":[{"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/media?parent=19841"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/categories?post=19841"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/tags?post=19841"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}