英国《自然》（Nature）杂志最近发表的一篇学术论文称，一种塔斯马尼亚蜥蜴能够根据气候条件的不同而决定是繁育雄性后代还是雌性后代。该发现表明，气候变化已成为影响许多冷血动物进化过程的重要因素。
这种名为雪蜥（Snow Skink）的小型长尾蜥蜴主要生活在澳大利亚的塔斯马尼亚岛，在温暖的低地和寒冷的高原上都有分布。英国牛津大学研究人员发现，在海拔1000米左右的地带，雪蜥没有显着的生育性别偏好，其后代性别比例比较均衡，雌雄数量大致相当；而在海拔较低的地区，雪蜥的生育性别偏好则比较明显，在生殖期处于阴冷气候的情况下，其生育的后代多为雄性，而如果生殖期间气候温暖，它们生育的后代则多为雌性。
研究人员指出，受环境影响，雪蜥已经进化到依靠两种因素决定后代性别的阶段：一种是遗传因素，另一种则是温度因素。之所以它们选择在温暖条件下生育雌性后代，是因为在这种气候环境下，蜥蜴会长得更快，体型也会更大一些。体型大小对雌蜥蜴来说十分重要，而对于雄性蜥蜴则显得无关紧要。
研究人员表示，该发现有助于科学家理解气候对动物习性的影响，以及动物种群是如何在不同性别决定机制之间进行快速转换的。雪蜥蜴的繁育特性表明，当某一性别的后代在生长发育过程中占据优势的时候，一些冷血动物就会进化出相应的后代性别偏好机制，而气候无疑是促成某一性别后代占据优势的最常见原因，气候变化成为影响这一进化的重要因素。（生物谷Bioon.com）
生物谷推荐英文摘要：
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.
