Partenogenez d\u00f6llenmesiz \u00fcreme. Gerek hayvanlarda, gerek bitkilerde d\u00f6llenmemi\u015f bir di\u015fi gametin geli\u015fip yeni bir birey meydana getirmesine denir. Bu a\u00e7\u0131dan partenogenez ile dald\u0131rma, \u00e7elik ya da tomurcukla \u00fcreme gibi do\u011frudan do\u011fruya \u00fcremeleri birbirine kar\u0131\u015ft\u0131rmamak gerekir. \u00c7\u00fcnk\u00fc bu \u00e7e\u015fit \u00fcremelerde d\u00f6llenme yoktur, ancak ba\u015flang\u0131\u00e7 h\u00fccresi di\u011fer somatik sa\u011flayan h\u00fccreler cinsel \u00fcreme h\u00fccreleri(di\u015fi ve erkek gamet) de\u011fildir.<\/p>\n
Partenogenezin de bir\u00e7ok \u00e7e\u015fidi vard\u0131r. En katk\u0131s\u0131z partenogenez, erke\u011fi olmayan t\u00fcrlerde (daphnia) ya da \u00e7ok az erke\u011fi bulunan t\u00fcrlerde (phasma) g\u00f6r\u00fclen partenogenezdir. Partenogenezin en \u00e7ok g\u00f6r\u00fclen bi\u00e7imlerinden biri mevsimlik olan\u0131d\u0131r. Asma biti ba\u015fta olmak \u00fczere birtak\u0131m bitkileri yaz\u0131n \u00e7iftle\u015fmezler, di\u015filer do\u011frudan do\u011fruya yumurtla ve bunlardan yeni yavrular olu\u015fur, ama k\u0131\u015fa dayan\u0131kl\u0131 yumurtalar yumurtlamak i\u00e7in sonbaharda \u00e7iftle\u015firler. Ar\u0131larda (bal ar\u0131s\u0131) anaar\u0131 ilk \u00e7iftle\u015fme u\u00e7u\u015funda edinip sperma kesesinde biriktirdi\u011fi erkek gametlerle kendi yumurtalar\u0131n\u0131 d\u00f6llendirerek peteklere b\u0131rak\u0131r ve y\u0131llarca (en \u00e7ok be\u015f y\u0131l) bunlardan di\u015fi olan i\u015f\u00e7i ar\u0131lar do\u011far. Arada bir d\u00f6llemedi\u011fi yumurtalardan erkek ar\u0131lar olu\u015fur. Sperma kesesinde hi\u00e7 sperma kalmad\u0131\u011f\u0131 zaman yurtlad\u0131klar\u0131ndansa hep erkek ar\u0131lar do\u011far. O zaman ar\u0131c\u0131lar bu ya\u015fl\u0131 anaar\u0131lar\u0131 yakalay\u0131p kovandan atarlar. Deneysel olarak da laboratuvarlarda pek \u00e7ok partenogenez halleri yarat\u0131lm\u0131\u015ft\u0131r (Leob Delage, Bataillon vb.). Bunlarda g\u00f6r\u00fclen ilgin\u00e7 ve ortak yan, herhangi bir \u015fekilde uyar\u0131lan (i\u011fne ile \u00e7izme, bir noktas\u0131n\u0131 delme vb.) her yumurtan\u0131n harekete ge\u00e7erek \u00e7o\u011falmaya ba\u015flamas\u0131d\u0131r.<\/p>\n
Partenogenez olay\u0131 insanlarda da olabilir mi?<\/p>\n
Partenogenez, e\u015feyli \u00fcreme tipleri alt\u0131nda s\u0131n\u0131flanmas\u0131na kar\u015f\u0131n, asl\u0131nda ger\u00e7ek bir e\u015feyli \u00fcreme karakteri ta\u015f\u0131m\u0131yor (E\u015feyli \u00fcreme alt\u0131nda s\u0131n\u0131flanmas\u0131n\u0131n nedeni, mayoz b\u00f6l\u00fcnmeyle olu\u015fan bir e\u015fey h\u00fccresinin bu s\u00fcre\u00e7te yer almas\u0131). Yumurta h\u00fccresi d\u00f6llenme olmaks\u0131z\u0131n geli\u015fiyor ve bu nedenle de haploid (n say\u0131da kromozom ta\u015f\u0131yan) bir birey meydana geliyor. <\/p>\n
\u0130nsanda tek bir kromozomun bile haploid olarak kal\u0131tlanmas\u0131, fizyolojik ve patolojiksendromlar\u0131n hatta bazen de lethal (\u00f6ld\u00fcr\u00fcc\u00fc) \u00f6zelliklerin ortaya \u00e7\u0131kmas\u0131na neden oldu\u011fu i\u00e7in, partenogenetik bir \u00fcreme bizler i\u00e7in s\u00f6z konusu de\u011fil. Bu konuda baz\u0131 \u00e7al\u0131\u015fmalar yap\u0131lm\u0131\u015f olmas\u0131na kar\u015f\u0131n, hen\u00fcz ba\u015far\u0131l\u0131 bir sonu\u00e7 al\u0131namad\u0131. baz\u0131
\nTav\u015fanlarda partenogenez ise, 1936 y\u0131l\u0131nda Gregory Pincus adl\u0131 ara\u015ft\u0131rmac\u0131 taraf\u0131ndan \u00e7al\u0131\u015f\u0131ld\u0131. Is\u0131 de\u011fi\u015fikli\u011fi ve kimyasal ajanlarla uyar\u0131lan tav\u015fan yumurta h\u00fccreleriyle yap\u0131lan bu \u00e7al\u0131\u015fma, hen\u00fcz memeliler konusundaki tek \u00f6rnek.<\/p>\n","protected":false},"excerpt":{"rendered":"
Partenogenez d\u00f6llenmesiz \u00fcreme. Gerek hayvanlarda, gerek bitkilerde d\u00f6llenmemi\u015f bir di\u015fi gametin geli\u015fip yeni bir birey meydana getirmesine denir. Bu a\u00e7\u0131dan partenogenez ile dald\u0131rma, \u00e7elik ya da tomurcukla \u00fcreme gibi do\u011frudan do\u011fruya \u00fcremeleri birbirine kar\u0131\u015ft\u0131rmamak gerekir. \u00c7\u00fcnk\u00fc bu \u00e7e\u015fit \u00fcremelerde d\u00f6llenme yoktur, ancak ba\u015flang\u0131\u00e7 h\u00fccresi di\u011fer somatik sa\u011flayan h\u00fccreler cinsel \u00fcreme h\u00fccreleri(di\u015fi ve erkek gamet) de\u011fildir. …<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1407,1403],"tags":[8233,8232,8230,5696,7692,8235,8234,8231],"class_list":["post-3615","post","type-post","status-publish","format-standard","hentry","category-fen-ve-teknoloji-odevleri","category-odevler","tag-bal-arisi","tag-daphnia","tag-dollenmesiz-ureme","tag-eseyli-ureme","tag-partenogenez","tag-patolojiksendromlar","tag-sperma","tag-tomurcukla-ureme"],"_links":{"self":[{"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/posts\/3615","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/comments?post=3615"}],"version-history":[{"count":0,"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/posts\/3615\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/media?parent=3615"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/categories?post=3615"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/tags?post=3615"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}