Humans, mice, and even kangaroos have an XX female:XY male system of sex determination, in which the Y harbors a male-dominant sex-determining gene SRY. Birds have the opposite, ZZ males and ZW females, and may use a dosage-sensitive Z-borne gene. Other reptiles have genetic sex but no visible sex chromosomes, or determine sex by temperature of egg incubation. How can we make sense of so much variation? How do systems change in evolution? Studies of some unlikely animals-platypus and dragon lizards, frogs and fish-confirm that evolutionary transitions have occurred between TSD and GSD systems, between XY and ZW systems, and even between male and female heterogametic systems. Here I explore nonmodel systems that offer some new perspectives on some venerable questions of sex and sex chromosomes.

中文翻译：

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怪异的动物基因组以及脊椎动物性别和性染色体的进化。

人类，小鼠，甚至袋鼠都具有XX雌雄异性的XY性别决定系统，其中Y携带着雄性决定性别的基因SRY。鸟类则相反，ZZ雄性和ZW雌性，可以使用剂量敏感的Z传播基因。其他爬行动物具有遗传性但无可见性染色体，或通过卵温育来确定性别。我们如何理解这么多变化？系统如何演变？对一些不太可能出现的动物（鸭嘴兽和龙蜥蜴，青蛙和鱼）的研究证实，TSD和GSD系统之间，XY和ZW系统之间，甚至雌雄异配系统之间都发生了进化过渡。在这里，我探讨了非模型系统，这些系统为有关性和性染色体的一些古老问题提供了一些新观点。