Holleley Clare E, Sarre Stephen D, O'Meally Denis, Georges Arthur
Australian National Wildlife Collection, National Research Collections Australia, CSIRO, Canberra, A.C.T., Australia.
Sex Dev. 2016;10(5-6):279-287. doi: 10.1159/000450972. Epub 2016 Oct 29.
Is sex a product of genes, the environment, or both? In this review, we describe the diversity of sex-determining mechanisms in reptiles, with a focus on systems that display gene-environment interactions. We summarise the field and laboratory-based evidence for the occurrence of environmental sex reversal in reptiles and ask whether this is a widespread evolutionary mechanism affecting the evolution of sex chromosomes and speciation in vertebrates. Sex determination systems exist across a continuum of genetic and environmental influences, blurring the lines between what was once considered a strict dichotomy between genetic sex determination and temperature-dependent sex determination. Across this spectrum, we identify the potential for sex reversal in species with clearly differentiated heteromorphic sex chromosomes (Pogona vitticeps, Bassiana duperreyi, Eremias multiocellata, Gekko japonicus), weakly differentiated homomorphic sex chromosomes (Niveoscincus ocellatus), and species with only a weak heritable predisposition for sex (Emys orbicularis, Trachemys scripta). We argue that sex reversal is widespread in reptiles (Testudines, Lacertidae, Agamidae, Scincidae, Gekkonidae) and has the potential to have an impact on individual fitness, resulting in reproductively, morphologically, and behaviourally unique phenotypes. Sex reversal is likely to be a powerful evolutionary force responsible for generating and maintaining lability and diversity in reptile sex-determining modes.
性别是基因、环境还是两者共同作用的产物？在这篇综述中，我们描述了爬行动物性别决定机制的多样性，重点关注显示基因-环境相互作用的系统。我们总结了基于野外和实验室的证据，证明爬行动物中存在环境性反转现象，并探讨这是否是一种影响脊椎动物性染色体进化和物种形成的广泛进化机制。性别决定系统存在于一系列遗传和环境影响的连续统一体中，模糊了曾经被认为是遗传性别决定和温度依赖性性别决定之间严格二分法的界限。在这个范围内，我们确定了具有明显分化的异型性染色体的物种（鬃狮蜥、杜氏石龙子、多斑沙蜥、日本壁虎）、弱分化的同型性染色体的物种（眼斑滑蜥）以及只有微弱遗传性别倾向的物种（欧洲池龟、红耳龟）中发生性反转的可能性。我们认为性反转在爬行动物（龟鳖目、蜥蜴科、鬣蜥科、石龙子科、壁虎科）中广泛存在，并且有可能影响个体适应性，导致在生殖、形态和行为上独特的表型。性反转可能是一种强大的进化力量，负责在爬行动物性决定模式中产生和维持变异性和多样性。
