英國《自然》（Nature）雜志最近發(fā)表的一篇學(xué)術(shù)論文稱，一種塔斯馬尼亞蜥蜴能夠根據(jù)氣候條件的不同而決定是繁育雄性后代還是雌性后代。該發(fā)現(xiàn)表明，氣候變化已成為影響許多冷血動物進化過程的重要因素,。
這種名為雪蜥（Snow Skink）的小型長尾蜥蜴主要生活在澳大利亞的塔斯馬尼亞島,，在溫暖的低地和寒冷的高原上都有分布,。英國牛津大學(xué)研究人員發(fā)現(xiàn)，在海拔1000米左右的地帶,，雪蜥沒有顯著的生育性別偏好,，其后代性別比例比較均衡，雌雄數(shù)量大致相當(dāng),；而在海拔較低的地區(qū),，雪蜥的生育性別偏好則比較明顯，在生殖期處于陰冷氣候的情況下,，其生育的后代多為雄性,，而如果生殖期間氣候溫暖，它們生育的后代則多為雌性,。
研究人員指出,，受環(huán)境影響，雪蜥已經(jīng)進化到依靠兩種因素決定后代性別的階段：一種是遺傳因素,，另一種則是溫度因素,。之所以它們選擇在溫暖條件下生育雌性后代，是因為在這種氣候環(huán)境下,，蜥蜴會長得更快,，體型也會更大一些。體型大小對雌蜥蜴來說十分重要,，而對于雄性蜥蜴則顯得無關(guān)緊要,。
研究人員表示，該發(fā)現(xiàn)有助于科學(xué)家理解氣候?qū)游锪?xí)性的影響,，以及動物種群是如何在不同性別決定機制之間進行快速轉(zhuǎn)換的,。雪蜥蜴的繁育特性表明，當(dāng)某一性別的后代在生長發(fā)育過程中占據(jù)優(yōu)勢的時候，一些冷血動物就會進化出相應(yīng)的后代性別偏好機制,，而氣候無疑是促成某一性別后代占據(jù)優(yōu)勢的最常見原因,，氣候變化成為影響這一進化的重要因素。（生物谷Bioon.com）
生物谷推薦英文摘要：
Nature doi:10.1038/nature09512
Climate-driven population divergence in sex-determining systems
Ido Pen,Tobias Uller,Barbara Feldmeyer,Anna Harts,Geoffrey M. While& Erik Wapstra
Sex determination is a fundamental biological process, yet its mechanisms are remarkably diverse1, 2. In vertebrates, sex can be determined by inherited genetic factors or by the temperature experienced during embryonic development2, 3. However, the evolutionary causes of this diversity remain unknown. Here we show that live-bearing lizards at different climatic extremes of the species’ distribution differ in their sex-determining mechanisms, with temperature-dependent sex determination in lowlands and genotypic sex determination in highlands. A theoretical model parameterized with field data accurately predicts this divergence in sex-determining systems and the consequence thereof for variation in cohort sex ratios among years. Furthermore, we show that divergent natural selection on sex determination across altitudes is caused by climatic effects on lizard life history and variation in the magnitude of between-year temperature fluctuations. Our results establish an adaptive explanation for intra-specific divergence in sex-determining systems driven by phenotypic plasticity and ecological selection, thereby providing a unifying framework for integrating the developmental, ecological and evolutionary basis for variation in vertebrate sex determination.
