{"id":32373,"date":"2019-02-11T01:22:42","date_gmt":"2019-02-10T22:22:42","guid":{"rendered":"https:\/\/bilimvegelecek.com.tr\/?p=32373"},"modified":"2019-02-11T01:08:47","modified_gmt":"2019-02-10T22:08:47","slug":"buyukanne-etkisi-kadinlarin-vazgecilmezligine-evrimsel-bir-kanit","status":"publish","type":"post","link":"https:\/\/bilimvegelecek.com.tr\/index.php\/2019\/02\/11\/buyukanne-etkisi-kadinlarin-vazgecilmezligine-evrimsel-bir-kanit","title":{"rendered":"B\u00fcy\u00fckanne etkisi: Kad\u0131nlar\u0131n vazge\u00e7ilmezli\u011fine evrimsel bir kan\u0131t"},"content":{"rendered":"

B\u00fcy\u00fckannelerimizi sevmek i\u00e7in \u00e7ok fazla sebebimiz var ama art\u0131k bu sevgiyi bilimsel a\u00e7\u0131dan me\u015fru k\u0131lan g\u00fc\u00e7l\u00fc gerek\u00e7elere de sahibiz. Birka\u00e7 kelimeyle \u00f6zetlemek gerekirse hayat\u0131m\u0131z\u0131 -k\u0131smen- b\u00fcy\u00fckannelere bor\u00e7luyuz! Finlandiya\u2019daki Turku \u00dcniversitesi b\u00fcnyesinde ger\u00e7ekle\u015ftirilen, b\u00fcy\u00fckannelerin varl\u0131\u011f\u0131yla torunlar\u0131n sa\u011fkal\u0131m\u0131 aras\u0131ndaki ili\u015fkinin incelendi\u011fi \u00e7al\u0131\u015fman\u0131n sonu\u00e7lar\u0131 \u00e7arp\u0131c\u0131. Ara\u015ft\u0131rmac\u0131lar\u0131n \u00e7\u0131k\u0131\u015f noktas\u0131n\u0131 olu\u015fturan as\u0131l soru, bu ili\u015fkinin biyolojik ya da evrimsel anlam\u0131n\u0131 ortaya koyuyor: Kad\u0131nlar neden \u00fcreme \u00e7a\u011flar\u0131n\u0131 tamamlad\u0131ktan sonra uzun s\u00fcre hayatta kalmaya devam eder? Ya da farkl\u0131 bir \u015fekilde form\u00fcle etmek gerekirse, kad\u0131nlar neden menapoza girer? Hatta, neden erkenden girer? Bu sorular, \u00f6zellikle de ilki, tuhaf ve ayk\u0131r\u0131 g\u00f6r\u00fcnebilir. Fakat sonu\u00e7ta insan da memeliler grubuna dahil bir canl\u0131; buna kar\u015f\u0131l\u0131k kendi grubunun mensuplar\u0131ndan farkl\u0131 olarak, hatta bir istisna halinde, di\u015finin\/kad\u0131n\u0131n \u00fcreme \u00e7a\u011f\u0131 erkenden sonlan\u0131rken ya\u015fam s\u00fcresi devam ediyor. Ya\u015fam\u0131n anlam\u0131n\u0131n hayatta kalmak ve \u00e7o\u011falmak oldu\u011fu biyoloji d\u00fcnyas\u0131nda bu pek de mant\u0131kl\u0131 bir tablo de\u011fil. Ara\u015ft\u0131rmac\u0131lar\u0131n s\u0131nad\u0131\u011f\u0131 i\u015fte bu ili\u015fki.<\/span><\/p>\n

Kad\u0131nlarda \u00fcreme \u00e7a\u011f\u0131 sonras\u0131 ya\u015fam s\u00fcresi uzunlu\u011funu anlamland\u0131ran bir hipotez zaten mevcut: Buna, \u201cb\u00fcy\u00fckanne hipotezi\u201d deniyor. \u0130\u00e7eri\u011fini tahmin etmekse zor de\u011fil; b\u00fcy\u00fckanneler kendileri \u00fcreyip evrimsel ba\u015far\u0131n\u0131n (buna biyolojide <\/span>fitness<\/span><\/i> deniyor; hayatta kalma ve \u00fcreme g\u00fcc\u00fcn\u00fc anlat\u0131yor) gere\u011fini yerine getirdikten sonra, torunlar\u0131n\u0131n yeti\u015ftirilmesine destek olarak en yak\u0131n genetik akrabalar\u0131n\u0131n (yani \u00e7ocuklar\u0131n\u0131n) -dolay\u0131s\u0131yla da t\u00fcr\u00fcn genelinin (yani t\u00fcm <\/span>Homo sapiens<\/span><\/i>\u2019lerin)- evrimsel ba\u015far\u0131s\u0131na katk\u0131 sa\u011fl\u0131yorlar. <\/span>Current Biology<\/span><\/i>\u2019nin 7 \u015eubat say\u0131s\u0131nda yer verilen \u00e7al\u0131\u015fmada Finlandiya toplumunun sanayi \u00f6ncesi d\u00f6nemi merkeze al\u0131nm\u0131\u015f ve 1731-1895 y\u0131llar\u0131 aras\u0131ndaki kilise kay\u0131tlar\u0131 incelenerek ayr\u0131nt\u0131l\u0131 istatistikler \u00e7\u0131kar\u0131lm\u0131\u015f. Elbette toplumlar\u0131n sanayi \u00f6ncesi ko\u015fullar\u0131yla bug\u00fcnk\u00fc ko\u015fullar\u0131 aras\u0131nda u\u00e7urum var; dolay\u0131s\u0131yla b\u00fcy\u00fckannelere duyulan ihtiya\u00e7 da bu ko\u015fullar do\u011frultusunda farkl\u0131 bir \u015fekle kavu\u015fuyor. Ancak biyolojik tarihimizin ancak \u00e7ok k\u00fc\u00e7\u00fck bir k\u0131sm\u0131 sanayi toplumuna kar\u015f\u0131l\u0131k geliyor. Dolay\u0131s\u0131yla daha eski d\u00f6nemleri incelemek ve biyolojimizle ili\u015fkisi ba\u011flam\u0131nda tahmin y\u00fcr\u00fctmek son derece makul g\u00f6r\u00fcn\u00fcyor. Nitekim \u00e7al\u0131\u015fman\u0131n kapsad\u0131\u011f\u0131 164 y\u0131ll\u0131k evre \u00e7ocuk \u00f6l\u00fcmlerinin a\u015f\u0131r\u0131 y\u00fcksek oldu\u011fu zamanlar: Kay\u0131tlar her 3 \u00e7ocuktan 1\u2019inin 5 ya\u015f\u0131ndan \u00f6nce, her 2 \u00e7ocuktan 1\u2019inin de 15\u2019ine varmadan, enfeksiyon ve solunum hastal\u0131klar\u0131 ba\u015fta olmak \u00fczere \u00e7e\u015fitli sebeplerle hayat\u0131n\u0131 kaybetti\u011fini g\u00f6steriyor. Rakamlar, 50 ya\u015f\u0131n\u0131 a\u015fabilen kad\u0131nlar\u0131n torunlar\u0131yla ortalama 5 ila 10 y\u0131l ge\u00e7irdi\u011fini ortaya koyuyor. Peki anneanne veya babaanneleriyle ayn\u0131 evi payla\u015fan toplam 5.815 torunun hayatta kalma oranlar\u0131 ger\u00e7ekten de b\u00fcy\u00fckanne hipotezini do\u011fruluyor mu? Kesinlikle evet!<\/span><\/p>\n

Babaanne anneanne \u00e7at\u0131\u015fmas\u0131<\/b><\/p>\n

B\u00fcy\u00fckannenin deste\u011finin en kritik oldu\u011fu d\u00f6nem \u00e7ocu\u011fun s\u00fctten kesildi\u011fi evre, yani 2-5 ya\u015f aras\u0131: Kay\u0131tlar (50-75 ya\u015f aral\u0131\u011f\u0131ndaki) b\u00fcy\u00fckannesiyle birlikte ya\u015fayan \u00e7ocuklarda hayatta kalma oran\u0131n\u0131n %30 artt\u0131\u011f\u0131n\u0131 g\u00f6steriyor. Bir di\u011fer ilgin\u00e7 tespit bu noktada anneanne ve babaanne aras\u0131ndaki fark: S\u00f6z konusu %30\u2019luk art\u0131\u015f sadece annenannenin varl\u0131\u011f\u0131nda ge\u00e7erli, babaannenin sa\u011fkal\u0131m \u00fczerinde g\u00f6r\u00fcn\u00fcr bir etkisi yok. En az\u0131ndan 75\u2019ine kadar durum b\u00f6yle; 75\u2019ten itibaren tablo tam tersine d\u00f6n\u00fcyor, \u00f6zellikle de s\u00f6z konusu olan babaanneyse. 75 ya\u015f \u00fczeri babaannenin varl\u0131\u011f\u0131 0-2 ya\u015f aral\u0131\u011f\u0131ndaki \u00e7ocuklarda sa\u011fkal\u0131m\u0131 %37 azalt\u0131yor. Bu sefer n\u00f6tr konumda olan anneanne, pozitif veya negatif etki g\u00f6stermiyor. Ara\u015ft\u0131rmac\u0131lar %37\u2019lik azalmay\u0131 annenin gebelik s\u00fcrecinde hissetti\u011fi strese ba\u011fl\u0131yor. \u00c7\u00fcnk\u00fc, \u00f6zellikle sanayisiz toplumlarda kendisi de net t\u00fcketici haline gelen ve toruna kalori sa\u011flayamayan 70-80 ya\u015f aral\u0131\u011f\u0131ndaki (muhtemelen sa\u011fl\u0131\u011f\u0131n\u0131 kaybetmi\u015f) b\u00fcy\u00fckanne, bebe\u011fin aleyhine olacak \u015fekilde kaynak rekabetinin par\u00e7as\u0131 haline geliyor. Ara\u015ft\u0131rmac\u0131lar bu oranlar\u0131 (\u00f6zellikle anneannenin %30\u2019luk katk\u0131s\u0131n\u0131) kad\u0131n\u0131n menapoz sonras\u0131ndaki uzam\u0131\u015f ya\u015fam s\u00fcresinin evrimsel ba\u015far\u0131 \u00fczerindeki dolayl\u0131 etkisi olarak yorumluyor. Sa\u011fkal\u0131ma bu \u015fekilde etki etmek elbette kad\u0131n\u0131n bu evredeki varl\u0131\u011f\u0131n\u0131, dolay\u0131s\u0131yla ya\u015fam s\u00fcresini do\u011fal se\u00e7ilime tabi k\u0131l\u0131yor.<\/span><\/p>\n

Derginin ayn\u0131 say\u0131s\u0131nda yay\u0131mlanan ve yine bu konuyu ele alan bir \u00e7al\u0131\u015fma daha var. Bunun da sonu\u00e7lar\u0131 Turku \u00dcniversitesi ara\u015ft\u0131rmac\u0131lar\u0131n\u0131n \u00e7\u0131kar\u0131mlar\u0131yla \u00f6rt\u00fc\u015f\u00fcyor. Yaln\u0131z, Kanada\u2019daki Bishop \u00dcniversitesi b\u00fcnyesinde y\u00fcr\u00fct\u00fclen bu ara\u015ft\u0131rmada ayn\u0131 mesele farkl\u0131 bir \u00f6l\u00e7\u00fct kullan\u0131larak ele al\u0131nm\u0131\u015f: Di\u011fer ara\u015ft\u0131rmadan farkl\u0131 olarak b\u00fcy\u00fckannenin \u00e7ocuklar\u0131ndan\/torunlar\u0131ndan ayr\u0131 ya\u015fad\u0131\u011f\u0131 ba\u011flamdaki etkisi anla\u015f\u0131lmaya \u00e7al\u0131\u015f\u0131lm\u0131\u015f. 1608-1799 aras\u0131nda Kanada\u2019n\u0131n St. Lawrence Vadisi b\u00f6lgesindeki Frans\u0131z yerle\u015fimcilere ait kay\u0131tlar, k\u0131zlar\u0131ndan ve torunlar\u0131ndan 0 ila 325 km uzakta ya\u015fayan 3.382 b\u00fcy\u00fckannenin \u00fcreme verileri \u00fczerindeki etkisi bak\u0131m\u0131ndan incelenmi\u015f. Sonu\u00e7lar yine \u00e7ok bariz bir b\u00fcy\u00fckanne etkisine i\u015faret ediyor: Pozitif ba\u011flant\u0131 mesafeyle azal\u0131yor olmakla birlikte, annesi hayatta olan k\u0131zlar hem daha erken ya\u015fta hem de daha fazla say\u0131da \u00e7ocuk do\u011furmu\u015f.<\/span><\/p>\n

Elbette t\u00fcm bu veriler menapoz denen olgunun neden evrimle\u015fmi\u015f oldu\u011funa dair \u00e7ok kesin bir \u015fey s\u00f6ylemiyor. Sonu\u00e7ta mesele t\u00fcr\u00fcn evrimsel ba\u015far\u0131s\u0131na katk\u0131ysa, kad\u0131n\u0131n bunu do\u011frudan kendi do\u011furganl\u0131\u011f\u0131 \u00fczerinden sa\u011flamas\u0131, ba\u015fka biri \u00fczerinden dolayl\u0131 olarak sa\u011flamas\u0131ndan daha mant\u0131kl\u0131 de\u011fil mi? O ki\u015fi kendi k\u0131z\u0131 bile olsa\u2026 Ara\u015ft\u0131rmac\u0131lar\u0131n bunu, nesiller aras\u0131 \u00fcreme rekabetini, yani ayn\u0131 \u00e7at\u0131 alt\u0131nda ya\u015fayan di\u015filer aras\u0131ndaki kaynak rekabetini engelleme gereklili\u011fiyle a\u00e7\u0131kl\u0131yor. Menapoz mekanizmas\u0131 sayesinde kendi \u00fcreme s\u00fcrecini tamamlayan kad\u0131n, ikinci neslin \u00fcremesine destek olarak t\u00fcr\u00fcn evrimsel ba\u015far\u0131s\u0131na daha fazla katk\u0131 sa\u011fl\u0131yor olabilir. Tabii bu ak\u0131l y\u00fcr\u00fctmenin de yeni \u00e7al\u0131\u015fmalarla s\u0131nanmas\u0131 gerekiyor, zira her iki \u00e7al\u0131\u015fmada da sadece menapoz sonras\u0131ndaki b\u00fcy\u00fckanneler ele al\u0131nm\u0131\u015f.<\/span><\/p>\n

Son olarak erkeklerin, yani b\u00fcy\u00fckbabalar\u0131n rol\u00fcn\u00fc merak edenler olabilir\u2026 Ne yaz\u0131k ki erkekler tam bir etkisiz eleman: B\u00fcy\u00fckbabalar\u0131n torunlar\u0131n sa\u011fkal\u0131m\u0131 \u00fczerinde herhangi bir etkisi yok. Kad\u0131n ve erke\u011fin ya\u015fam s\u00fcreleri aras\u0131nda belirgin bir fark bulunmuyor fakat yine de erkeklerin ya\u015fam s\u00fcresinin ba\u011fland\u0131\u011f\u0131 bir \u201cb\u00fcy\u00fckbaba hipotezi\u201d s\u00f6z konusu de\u011fil. O kadar ki ara\u015ft\u0131rmac\u0131lar erke\u011fin ya\u015fam s\u00fcresinin, kad\u0131n\u0131n ya\u015fam s\u00fcresi evrimiyle \u201cs\u00fcr\u00fcklenen\u201d (yani se\u00e7ilimle ili\u015fkili olmayan) bir nevi yan \u00fcr\u00fcn oldu\u011fu ihtimali \u00fczerinde duruyor.<\/span><\/p>\n

Kaynak
\n<\/b>1) Chapman N. Simon ve ark., \u201cLimits to Fitness Benefits of Prolonged Post-reproductive Lifespan in Women\u201d, <\/span>Current Biology<\/span><\/i>, 7 \u015eubat 2019.
\n<\/span>2) Engelhardt C. Sacha ve ark., \u201cUsing Geographic Distance as a Potential Proxy for Help in the Assessment of the Grandmother Hypothesis\u201d, <\/span>Current Biology<\/span><\/i>, 7 \u015eubat 2019.<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"

B\u00fcy\u00fckannelerimizi sevmek i\u00e7in \u00e7ok fazla sebebimiz var ama art\u0131k bu sevgiyi bilimsel a\u00e7\u0131dan me\u015fru k\u0131lan g\u00fc\u00e7l\u00fc gerek\u00e7elere de sahibiz. Birka\u00e7 kelimeyle \u00f6zetlemek gerekirse hayat\u0131m\u0131z\u0131 -k\u0131smen- b\u00fcy\u00fckannelere bor\u00e7luyuz! Finlandiya\u2019daki Turku \u00dcniversitesi b\u00fcnyesinde ger\u00e7ekle\u015ftirilen, b\u00fcy\u00fckannelerin varl\u0131\u011f\u0131yla torunlar\u0131n sa\u011fkal\u0131m\u0131 aras\u0131ndaki ili\u015fkinin incelendi\u011fi \u00e7al\u0131\u015fman\u0131n sonu\u00e7lar\u0131 \u00e7arp\u0131c\u0131. Ara\u015ft\u0131rmac\u0131lar\u0131n \u00e7\u0131k\u0131\u015f noktas\u0131n\u0131 olu\u015fturan as\u0131l soru, bu ili\u015fkinin biyolojik ya da evrimsel anlam\u0131n\u0131 […]<\/p>\n","protected":false},"author":184,"featured_media":32371,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[19,21,29],"tags":[4549,4550,4548,4551],"class_list":["post-32373","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-bilim-gundemi","category-biyoloji","category-toplum","tag-buyukanne-hipotezi","tag-kaynak-rekabeti","tag-menapoz","tag-sagkalim"],"acf":[],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/posts\/32373","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\/184"}],"replies":[{"embeddable":true,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/comments?post=32373"}],"version-history":[{"count":0,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/posts\/32373\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/media\/32371"}],"wp:attachment":[{"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/media?parent=32373"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/categories?post=32373"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/tags?post=32373"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}