Sex Chromosome Evolution in Lizards: Independent Origins and Rapid Transitions
Sex Chromosome Evolution in Lizards: Independent Origins and Rapid Transitions
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DOI：
10.1159/000300507
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发表时间：
2009-01-01
影响因子：
1.7
通讯作者：
Georges, A.
中科院分区：
文献类型：
--
作者：
Ezaz, T.;Sarre, S. D.;Georges, A.
爬行动物集中体现了羊膜动物生殖和性别决定模式和机制的变异性。这些模式包括雌雄异体（异性）和孤雌生殖、卵生、胎生和卵胎生、雄性（XX/XY）和雌性（ZZ/ZW）异配性的基因型性别决定（GSD）和温度依赖性性别决定（TSD）。蜥蜴（有鳞目，蜥亚目）特别令人着迷，因为性别决定机制的分布没有显示出明显的系统发育分离。这意味着 TSD 和 GSD 之间以及 XY 和 ZW 性染色体系统之间存在多次转变。大约1000种蜥蜴已被进行核型分析，其中只有不到200种有性染色体，但它们在形态和退化程度方面表现出显着的多样性。性染色体的高度多样性以及患有 TSD 的物种的存在，意味着性染色体的多个且独立的起源，并表明蜥蜴的性别决定机制极其不稳定。在本文中，我们回顾了蜥蜴性染色体的知识现状以及性别决定机制和性染色体形式在科内和科间的分布。我们首次建立了蜥蜴家族中雌性异配性的发生与 TSD 之间的关联，并提出了雌性异配性和 TSD 可能共同进化的机制。我们认为，蜥蜴的性别决定可能比以前认为的更多是性染色体和温度之间相互作用的结果，因此性别决定模式受到异配性的性质以及温度敏感性和性染色体退化阶段的影响。版权所有 (C) 2010 S. Karger AG，巴塞尔
Reptiles epitomize the variability of reproductive and sex determining modes and mechanisms among amniotes. These modes include gonochorism (separate sexes) and parthenogenesis, oviparity, viviparity, and ovoviviparity, genotypic sex determination (GSD) with male (XX/XY) and female (ZZ/ZW) heterogamety and temperature-dependent sex determination (TSD). Lizards (order Squamata, suborder Sauria) are particularly fascinating because the distribution of sex-determining mechanisms shows no clear phylogenetic segregation. This implies that there have been multiple transitions between TSD and GSD, and between XY and ZW sex chromosome systems. Approximately 1,000 species of lizards have been karyotyped and among those, fewer than 200 species have sex chromosomes, yet they display remarkable diversity in morphology and degree of degeneration. The high diversity of sex chromosomes as well as the presence of species with TSD, imply multiple and independent origins of sex chromosomes, and suggest that the mechanisms of sex determination are extremely labile in lizards. In this paper, we review the current state of knowledge of sex chromosomes in lizards and the distribution of sex determining mechanisms and sex chromosome forms within and among families. We establish for the first time an association between the occurrence of female heterogamety and TSD within lizard families, and propose mechanisms by which female heterogamety and TSD may have co-evolved. We suggest that lizard sex determination may be much more the result of an interplay between sex chromosomes and temperature than previously thought, such that the sex determination mode is influenced by the nature of heterogamety as well as temperature sensitivity and the stage of sex chromosome degeneration. Copyright (C) 2010 S. Karger AG, Basel