Lin Jian-Qing, Yu Jun, Sun Li, Fang Sheng-Guo
MOE Key Laboratory of Biosystems Homeostasis and Protection, State Conservation Centre for Gene Resources of Endangered Wildlife, College of Life Sciences, Zhejiang University, Hangzhou, China.
Front Genet. 2021 Mar 11;12:655900. doi: 10.3389/fgene.2021.655900. eCollection 2021.
The sexes of Chinese alligators are determined during embryonic development and remain fixed thereafter. In this study, we investigated the genetic and epigenetic mechanisms underlying sex maintenance in Chinese alligators through RNA sequencing and bisulfite sequencing data analyses of the adult gonads. We identified the genes and pathways (e. g., DMRT1-SOX9-AMH pathway for males and oocyte meiotic maturation pathway for females) involved in male and female sex maintenance and gonadal development of adult Chinese alligators. In contrast to their expression patterns in the embryo, both and the steroid hormone biosynthesis related genes showed a male-biased expression in adult gonads. The overall DNA methylation density and level were higher in testes than in ovaries. Hypermethylation in the gene bodies enhanced the expression of male-biased genes (such as DMRT1-SOX9-AMH and steroid hormone biosynthesis related genes) in the testis, as opposed to the normalization of gene expression. Our results provide insights into the genetic and epigenetic mechanisms underlying sex maintenance in adult Chinese alligators, and are expected to contribute to the development of scientific programs for the successful conservation of this endangered species.
扬子鳄的性别在胚胎发育期间就已确定，此后保持不变。在本研究中，我们通过对成年扬子鳄性腺进行RNA测序和亚硫酸氢盐测序数据分析，探究了扬子鳄性别维持的遗传和表观遗传机制。我们确定了参与成年扬子鳄雌雄性别维持和性腺发育的基因及信号通路（例如，雄性的DMRT1-SOX9-AMH信号通路和雌性的卵母细胞减数分裂成熟信号通路）。与它们在胚胎中的表达模式不同，[此处原文缺失部分内容]和类固醇激素生物合成相关基因在成年性腺中均表现出雄性偏向性表达。睾丸中的总体DNA甲基化密度和水平高于卵巢。基因体内的高甲基化增强了睾丸中雄性偏向性基因（如DMRT1-SOX9-AMH和类固醇激素生物合成相关基因）的表达，而不是使基因表达正常化。我们的研究结果为成年扬子鳄性别维持的遗传和表观遗传机制提供了见解，并有望为成功保护这一濒危物种的科学计划的制定做出贡献。
