Incubation temperature and parental identity determine sex in the Australian agamid lizard Ctenophorus pictus
Incubation temperature and parental identity determine sex in the Australian agamid lizard Ctenophorus pictus
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DOI：
10.1002/ece3.4466
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发表时间：
2018-10-01
影响因子：
2.6
通讯作者：
Olsson, Mats
中科院分区：
文献类型：
--
作者：
Hansson, Alexander;Olsson, Mats
澳大利亚蜥蜴的性别决定显示出一个由不同机制组成的复杂框架，甚至在密切相关的类群之间也存在差异。显然，将这些物种分别分类为具有遗传性别决定（GSD）或环境性别决定（ESD）与经验数据不一致。尽管该组中的许多物种表现出温度依赖性性别决定（TSD），但最近的证据表明还有额外的遗传或表观遗传效应。一个提出的模型解释了 TSD 在短命无脊椎动物中的适应性意义和进化，预测选择将有利于具有激烈雄性竞争的物种的温度偏差性别比例。在这里，我们在（接近）恒定温度下进行实验孵化，以测试澳大利亚彩龙（Ctenophorus pictus）的性别是否受到温度的影响，之前的研究尚未就温度对该物种的作用达成一致。在这项研究中，孵化温度和亲本身份影响孵化性别，这表明环境和遗传学可能共同决定该物种的性别。尽管我们的结果与 TSD 一致，但我们的数据不能排除温度与性别对卵或幼体死亡率的影响。然而，我们的发现以及在该属内密切相关的物种中观察到的性别决定系统的差异可能为解决性别决定系统进化中的基本问题提供新的机会。
Sex determination in Australian agamid lizards shows a complex framework of different mechanisms, varying even among closely related taxa. It is clear that discrete classification of these species as either having genetic (GSD) or environmental sex determination (ESD) does not agree with empirical data. Although many species in this group show temperature-dependent sex determination (TSD), recent evidence suggests additional genetic or epigenetic effects. A proposed model explaining the adaptive significance and evolution of TSD in short-lived agamids predicts that selection will favor temperature-biased sex ratios in species with intense male-male competition. Here, we use experimental incubation at (near) constant temperatures to test whether the sex of Australian painted dragons (Ctenophorus pictus) is influenced by temperature, building on previous research yet to have reached an agreement regarding the role of temperature in this species. In this study, incubation temperature and parental identity affected hatchling sex suggesting that environment and genetics may work in concert to determine sex in this species. Although our results are consistent with TSD, our data cannot rule out a temperature-by-sex effect on egg or hatchling mortality. However, our findings together with the observed differences of sex determination systems in closely related species within this genus may provide novel opportunities to address fundamental questions in the evolution of sex determination systems.