State Key Laboratory of Developmental Biology of Freshwater Fish, Engineering Research Center of Polyploid Fish Reproduction and Breeding of the State Education Ministry, College of Life Sciences, Hunan Normal University, Changsha, 410081, China.
Nansha-South China Agricultural University Fishery Research Institute, Guangzhou, 511457, China.
Sci China Life Sci. 2024 Nov;67(11):2444-2458. doi: 10.1007/s11427-023-2694-5. Epub 2024 Aug 9.
Autotetraploid Carassius auratus is a stable hereditary autotetraploid fish resulting from the hybridization of Carassius auratus red var. (RCC, ♀) × Megalobrama amblycephala (BSB, ♂), containing four sets of RCC chromosomes. However, the molecular mechanism underlying the determination of sex in this species remains largely unknown. Currently, there lacks a full understanding of the molecular mechanisms governing sex determination and specific molecular markers to differentiate sex in this species. In this study, 25,801,677 SNPs (Single-nucleotide polymorphism) and 6,210,306 Indels (insertion-deletion) were obtained from whole-genome resequencing of 100 individuals (including 50 female and 50 male). Further identification confirmed the candidate chromosomes as Chr46B, with the sex-determining region located at Chr46B: 22,500,000-22,800,000 bp. Based on the male-specific insertion (26 bp) within the candidate sex-determining region, a pair of sex-specific molecular markers has been identified. In addition, based on the screening of candidate sex-determining region genes and RT-qPCR validation analysis, ADAM10, AQP9 and tc1a were identified as candidate sex-determining genes. These findings provide a robust foundation for investigating sex determination mechanisms in fish, the evolution of sex chromosomes, and the development of monosex populations.
金鱼是一种稳定的遗传同源四倍体鱼类，由红鲫鱼（♀）和团头鲂（♂）杂交产生，含有四套红鲫鱼染色体。然而，该物种性别决定的分子机制在很大程度上仍然未知。目前，人们对该物种性别决定的分子机制缺乏全面的了解，也没有特定的分子标记来区分其性别。本研究通过对 100 个个体（包括 50 个雌性和 50 个雄性）进行全基因组重测序，获得了 25,801,677 个 SNP（单核苷酸多态性）和 6,210,306 个 Indels（插入缺失）。进一步的鉴定证实候选染色体为 Chr46B，性别决定区位于 Chr46B：22,500,000-22,800,000bp。基于候选性别决定区的雄性特异性插入（26bp），鉴定出一对性别特异性分子标记。此外，基于候选性别决定区基因的筛选和 RT-qPCR 验证分析，鉴定出 ADAM10、AQP9 和 tc1a 为候选性别决定基因。这些发现为研究鱼类性别决定机制、性染色体的进化以及单性种群的发展提供了坚实的基础。
