School of Zoology, University of Tasmania, Hobart, Tasmania, Australia. erik.wapstra @ utas.edu.au
Sex Dev. 2010;4(1-2):110-8. doi: 10.1159/000272459. Epub 2009 Dec 29.
Reptiles possess a wide variety of sex determining mechanisms, more so than any other vertebrate group. They offer outstanding opportunities to understand the evolutionary transitions between modes of sex determination. In this review, we argue that sex allocation theory is fundamental for understanding the selective causes of such shifts. Whether selection for biased sex allocation actually results in evolutionary shifts in sex determination depends on the overall strength, direction and consistency of selection and to what extent existing reproductive systems can establish novel links between factors causing sex-specific fitness and mechanisms of sex determination. Perhaps one of the most exciting advances in recent years has been the phylogenetically diverse range in reptile taxa that form the basis of research on the evolution of sex determination. The traditional use of long-lived oviparous species (especially turtles and crocodiles) is now expanded to include a range of short-lived taxa that exhibit both genetic sex determination and environment-/temperature-dependent sex determination (particularly agamid lizards), as well as a greater emphasis on viviparous species. If selection on differential sex allocation is a key selective pressure for the evolution of sex-determining mechanisms, these taxa will provide considerable insights into the integrated fields of sex allocation biology and sex determination.
爬行动物拥有各种各样的性别决定机制，比任何其他脊椎动物群体都多。它们为了解性别决定模式之间的进化转变提供了极好的机会。在这篇综述中，我们认为性别分配理论对于理解这种转变的选择原因是基本的。选择偏向性的性别分配是否真的导致性别决定的进化转变，取决于选择的整体强度、方向和一致性，以及现有生殖系统在多大程度上能够在导致性别特异性适应性的因素和性别决定机制之间建立新的联系。近年来，最令人兴奋的进展之一是，在研究性别决定进化的基础上，爬行动物类群在系统发育上具有多样性。长期以来，人们一直使用长寿的卵生物种（尤其是海龟和鳄鱼）作为研究基础，现在已经扩展到包括一系列短寿命的物种，这些物种既表现出遗传性别决定，也表现出环境/温度依赖性性别决定（特别是鬣蜥科蜥蜴），并且更加重视胎生物种。如果对差异性别分配的选择是性别决定机制进化的关键选择压力，那么这些类群将为性别分配生物学和性别决定的综合领域提供重要的见解。
