Sex determination (SD) is a highly diverse and complex mechanism. In vertebrates, one of the first morphological differences between the sexes is the timing of initiation of the first meiosis, where its initiation occurs first in female and later in male. Thus, SD is intimately related to the responsiveness of the germ cells to undergo meiosis in a sex-specific manner. In some vertebrates, it has been reported that the timing for meiosis entry would be under control of retinoic acid (RA), through activation of Stra8. In this study, we used a fish model species for sex determination and lacking the stra8 gene, the Japanese medaka (Oryzias latipes), to investigate the connection between RA and the sex determination pathway. Exogenous RA treatments act as a stress factor inhibiting germ cell differentiation probably by activation of dmrt1a and amh. Disruption of the RA degrading enzyme gene cyp26a1 induced precocious meiosis and oogenesis in embryos/hatchlings of female and even some males. Transcriptome analyzes of cyp26a1–/–adult gonads revealed upregulation of genes related to germ cell differentiation and meiosis, in both ovaries and testes. Our findings show that germ cells respond to RA in a stra8 independent model species. The responsiveness to RA is conferred by sex-related genes, restricting its action to the sex differentiation period in both sexes.

性别确定（SD）是高度多样化和复杂的机制。在脊椎动物中，性别之间的第一个形态差异是第一次减数分裂的起始时间，第一次减数分裂的起始时间在雌性中，然后在雄性中发生。因此，SD与生殖细胞以性别特异性方式进行减数分裂的反应性密切相关。据报道，在某些脊椎动物中，减数分裂进入的时机将通过激活维甲酸而受到视黄酸（RA）的控制。Stra8。在这项研究中，我们使用鱼类模型物种进行性别确定，但缺乏stra8 基因，日本东方稻），以研究RA与性别决定途径之间的联系。外源性RA治疗可能是通过激活MMP3来抑制生殖细胞分化的压力因子。dmrt1a 和 嗯。RA降解酶基因的破坏cyp26a1诱导雌性甚至某些雄性的胚胎/幼体早熟减数分裂和卵子发生。转录组分析cyp26a1-/-成年性腺揭示卵巢和睾丸中与生殖细胞分化和减数分裂相关的基因上调。我们的发现表明，生殖细胞对RA中的RA有反应。stra8独立的模型物种。性相关基因赋予对RA的反应性，将其作用限制在男女的性别分化时期。