(The Turkish Post) – Ara\u015ft\u0131rmac\u0131lar, D\u00fcnya’n\u0131n ilk \u00e7ok h\u00fccreli hayvanlar\u0131n\u0131n hangileri oldu\u011funa ve nas\u0131l g\u00f6r\u00fcnd\u00fckleri sorusuna yan\u0131t buldu.<\/p>\n
Bilim insanlar\u0131 y\u0131llard\u0131r, Latince ad\u0131 Porifera olan s\u00fcngerlerin ilk unvan\u0131na en yak\u0131n canl\u0131lar oldu\u011funu d\u00fc\u015f\u00fcn\u00fcyordu. Zira anatomileri son derece basit olan s\u00fcngerlerin bir sinir sistemi bile yok.<\/p>\n
Ancak yeni veriler, bu d\u00fc\u015f\u00fcnceye meydan okuyor.<\/p>\n
Hakemli bilimsel dergi Nature’da yay\u0131mlanan yeni ara\u015ft\u0131rmaya g\u00f6re, tarak denizanas\u0131 karma\u015f\u0131k bir sinir sistemine sahip olmas\u0131na ra\u011fmen “ilklik” unvan\u0131n\u0131 kazanabilir.<\/p>\n
Bilimsel ad\u0131 Ctenophora olan ve esasen denizanalar\u0131yla sadece uzaktan akraba bu canl\u0131 grubuna d\u00fcnya genelindeki sularda rastlanabilir.<\/p>\n
ABD’deki Kaliforniya \u00dcniversitesi’nden molek\u00fcler biyolog Daniel Rokhsar, “T\u00fcm hayvanlar\u0131n en yak\u0131n ortak atas\u0131 muhtemelen 600 veya 700 milyon y\u0131l \u00f6nce ya\u015fad\u0131. Yumu\u015fak v\u00fccutlu hayvanlar olduklar\u0131 ve do\u011frudan bir fosil kayd\u0131 b\u0131rakmad\u0131klar\u0131 i\u00e7in neye benzediklerini bilmek zor” ifadelerini kulland\u0131.<\/p>\n
Rokhsar ve meslekta\u015flar\u0131 bu zorlu\u011fun \u00fcstesinden gelmek i\u00e7in \u00e7e\u015fitli adaylar\u0131 molek\u00fcler d\u00fczeyde kar\u015f\u0131la\u015ft\u0131rmaya karar verdi.<\/p>\n
\u00d6nceki analizler yaln\u0131zca gen dizilerine odaklanm\u0131\u015f ve \u00e7eli\u015fkili sonu\u00e7lar vermi\u015fti. Zira baz\u0131 diziler, D\u00fcnya’da \u00f6nce s\u00fcngerlerin ortaya \u00e7\u0131kt\u0131\u011f\u0131n\u0131, di\u011ferleriyse tarakl\u0131 denizanalar\u0131n\u0131n ilk oldu\u011funu g\u00f6stermi\u015fti.<\/p>\n
Yeni ara\u015ft\u0131rmada ise bu canl\u0131lar\u0131n genetik molek\u00fclleri (kromozomlar) \u00fczerindeki gen dizilerinin d\u00fczenleni\u015f bi\u00e7imleri kar\u015f\u0131la\u015ft\u0131r\u0131ld\u0131.<\/p>\n
\u00c7al\u0131\u015fmada tarak denizanalar\u0131n\u0131n yan\u0131 s\u0131ra iki deniz s\u00fcngeri, iki tek h\u00fccreli hayvan (koanoflagellatlar ve amip) ve daha modern say\u0131lan di\u011fer hayvanlar yer ald\u0131.<\/p>\n
T\u00fcm hayvanlarda ayn\u0131 kromozom i\u00e7indeki gen dizilerinin ba\u011flanma \u015fekli belirgin bir modele uygundu. S\u00fcngerler ve daha modern hayvanlar\u0131n t\u00fcm\u00fc, nadir g\u00f6r\u00fclen bir kromozom f\u00fczyonu ve yeniden d\u00fczenleme s\u00fcreci sonucunda ortaya \u00e7\u0131kan \u00f6zellikleri ta\u015f\u0131yordu.<\/p>\n
Ancak bu \u00f6zellikler, genomlar\u0131 di\u011fer tek h\u00fccreli hayvanlara benzeyen tarakl\u0131 denizanas\u0131nda yoktu.<\/p>\n
Rokhsar, “Bu bir i\u015faret fi\u015fe\u011fiydi” ifadelerini kulland\u0131.<\/p>\n
Ekip buradan hareketle b\u00fcy\u00fck olas\u0131l\u0131kla \u00f6nce tarakl\u0131 denizanalar\u0131n\u0131n, ard\u0131ndan da s\u00fcngerlerin ortaya \u00e7\u0131kt\u0131\u011f\u0131 sonucuna vard\u0131.<\/p>\n
Buna g\u00f6re, s\u00fcngerler daha sonra yeni kar\u0131\u015f\u0131k kromozom dizilimlerini kendi soyundan gelen hayvanlara aktarmaya ba\u015flad\u0131. Bu da tarakl\u0131 denizanalar\u0131nda s\u00f6z konusu \u00f6zelliklerin neden g\u00f6r\u00fclmedi\u011fini a\u00e7\u0131kl\u0131yor.<\/p>\n
Schultz, “Bu eski evrimsel olay\u0131n parmak izleri, y\u00fcz milyonlarca y\u0131l sonra hayvanlar\u0131n genomlar\u0131nda hala mevcuttur” diyor. Ara\u015ft\u0131rman\u0131n ortak yazarlar\u0131ndan ve Viyana \u00dcniversitesi’nden biyoinformatik\u00e7i Darrin Schultz, “Bu eski evrimsel olay\u0131n parmak izleri, y\u00fcz milyonlarca y\u0131l sonra hayvanlar\u0131n genomlar\u0131nda halen mevcut” dedi: “Bu ara\u015ft\u0131rma bize hayvanlar\u0131 neyin hayvan yapt\u0131\u011f\u0131n\u0131 anlamam\u0131z i\u00e7in ba\u011flam sa\u011fl\u0131yor. \u00c7evrelerini nas\u0131l alg\u0131lad\u0131klar\u0131, nas\u0131l yedikleri ve nas\u0131l hareket ettikleri gibi hepimizin payla\u015ft\u0131\u011f\u0131 temel i\u015flevleri anlamam\u0131z\u0131 sa\u011flayacak.”<\/p>\n","protected":false},"excerpt":{"rendered":"
(The Turkish Post) – Ara\u015ft\u0131rmac\u0131lar, D\u00fcnya’n\u0131n ilk \u00e7ok h\u00fccreli hayvanlar\u0131n\u0131n hangileri oldu\u011funa ve nas\u0131l g\u00f6r\u00fcnd\u00fckleri sorusuna yan\u0131t buldu. Bilim insanlar\u0131 y\u0131llard\u0131r, Latince ad\u0131 Porifera olan s\u00fcngerlerin ilk unvan\u0131na en yak\u0131n canl\u0131lar oldu\u011funu d\u00fc\u015f\u00fcn\u00fcyordu. Zira anatomileri son derece basit olan s\u00fcngerlerin bir sinir sistemi bile yok. Ancak yeni veriler, bu d\u00fc\u015f\u00fcnceye meydan okuyor. Hakemli bilimsel dergi […]<\/p>\n","protected":false},"author":2,"featured_media":10521,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"jnews-multi-image_gallery":[],"jnews_single_post":{"source_name":"Independent","source_url":"https:\/\/www.indyturk.com\/node\/633686\/bi%CC%87li%CC%87m\/d%C3%BCnyan%C4%B1n-ilk-hayvan%C4%B1-bulunmu%C5%9F-olabilir-700-milyon-y%C4%B1l-%C3%B6nce-ortaya-%C3%A7%C4%B1kt%C4%B1","via_name":"","via_url":"","override_template":"0","override":[{"template":"1","single_blog_custom":"","parallax":"1","fullscreen":"1","layout":"right-sidebar","sidebar":"default-sidebar","second_sidebar":"default-sidebar","sticky_sidebar":"1","share_position":"topbottom","share_float_style":"share-monocrhome","show_share_counter":"0","show_view_counter":"0","show_featured":"1","show_post_meta":"1","show_post_author":"0","show_post_author_image":"1","show_post_date":"1","post_date_format":"default","post_date_format_custom":"Y\/m\/d","show_post_category":"0","show_post_reading_time":"1","post_reading_time_wpm":"300","show_zoom_button":"1","zoom_button_out_step":"4","zoom_button_in_step":"4","show_post_tag":"1","show_prev_next_post":"0","show_popup_post":"1","number_popup_post":"2","show_author_box":"1","show_post_related":"1","show_inline_post_related":"0"}],"override_image_size":"0","image_override":[{"single_post_thumbnail_size":"crop-715","single_post_gallery_size":"crop-500"}],"trending_post":"0","trending_post_position":"meta","trending_post_label":"Trending","sponsored_post":"0","sponsored_post_label":"Sponsored by","sponsored_post_name":"","sponsored_post_url":"","sponsored_post_logo_enable":"0","sponsored_post_logo":"","sponsored_post_desc":"","disable_ad":"0"},"jnews_primary_category":{"id":"107","hide":""},"jnews_override_bookmark_settings":{"override_bookmark_button":"0","override_show_bookmark_button":"0"},"jnews_social_meta":{"fb_title":"","fb_description":"","fb_image":"","twitter_title":"","twitter_description":"","twitter_image":""},"jnews_override_counter":{"override_view_counter":"0","view_counter_number":"0","override_share_counter":"0","share_counter_number":"0","override_like_counter":"0","like_counter_number":"0","override_dislike_counter":"0","dislike_counter_number":"0"},"footnotes":""},"categories":[1,107],"tags":[3052,3050,3051,1422],"class_list":["post-10516","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-son-haberler","category-yasam","tag-700-milyon-yil","tag-dunyanin-ilk-cok-hucreli-hayvani","tag-dunyanin-ilk-hayvani","tag-slider-manset"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.turkishpost.net\/ar\/wp-json\/wp\/v2\/posts\/10516","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.turkishpost.net\/ar\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.turkishpost.net\/ar\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.turkishpost.net\/ar\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.turkishpost.net\/ar\/wp-json\/wp\/v2\/comments?post=10516"}],"version-history":[{"count":0,"href":"https:\/\/www.turkishpost.net\/ar\/wp-json\/wp\/v2\/posts\/10516\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.turkishpost.net\/ar\/wp-json\/wp\/v2\/media\/10521"}],"wp:attachment":[{"href":"https:\/\/www.turkishpost.net\/ar\/wp-json\/wp\/v2\/media?parent=10516"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.turkishpost.net\/ar\/wp-json\/wp\/v2\/categories?post=10516"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.turkishpost.net\/ar\/wp-json\/wp\/v2\/tags?post=10516"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}