中文摘要：

性别决定是一个可塑的生物发育过程，一直以来都是进化生物学和发育生物学的研究热点。在脊椎动物中，性别决定的机制主要包括遗传性别决定（GSD）和环境性别决定（ESD）。GSD一般都是由位于性染色体上的决定基因启动一系列性别相关基因参与的级联信号通路，从而诱导原始生殖性腺发育成精巢（卵巢）的过程。尽管性别调控信号通路下游的基因在脊椎动物中是相对保守的，但是处于级联信号通路最上游的性别决定基因可能是不稳定的。截止目前，在脊椎动物中，已经发现了5个性别决定基因（SRY、DMRTl、DMY、DMW和AMHY）。本文综述了脊椎动物性别决定基因的研究进展，分析了高等脊椎动物和低等脊椎动物性别决定基因保守性的差异，推测这种差异可能是由于性染色体是否分化造成的，进而提出性别决定基因和性染色体演化关系的模型。

英文摘要：

Sex determination is a plastic biological developmental process, which has always the intriguing aspect in evolutionary biology and developmental biology. In vertebrates, the sex determination including genetic sex determination （GSD） and environmental sex determination （ESD） acts to differentiate an initially bipotential gonad primordium into either testes or ovaries. GSD is governed by a series of sex-related genes involving in genetic pathway that initiate by sex-determining gene during critical periods of gonadal development. Though many downstream genes in sex determination pathways are conserved, even among vertebrates and invertebrates, the upstream sex determination gene can vary even between closely related species. Up to now, five sex-determining genes （SRY, DMRT1, DMY, DMIV and AMHY） had been identified in vertebrates. This paper reviews the recent progress of sex-determining genes in vertebrate and analysis of the differences on the conservation of sex-determining genes between the higher vertebrates and lower vertebrates. We found that the sex-determining genes （SRY and DMRT1） are conserved in therian and aves, respectively,comparing to the sex-determining genes DMW, DMY and AMHY, which are unstable in their respective taxonomic systems. Correspondingly, the sex chromosomes in higher vertebrate attained high differentiation during their evolution, whereas no obvious （or even no） differentiation was observed in the sex chromosome of most extant lower vertebrates. Generally, the appearance of sex-determining gene in certain organism was always accompanied with the evolution of their sex chromosomes, which was defined by coevolution. We thus concluded that the difference of conservation on sex-determining genes between higher vertebrates and lower vertebrates may be caused by the sex chromosome differentiation or not. Following these conclusions, we then put forward two models on the relationship between sex-determining gene and sex chromosome evolution. One is the model of different