International Journal of Aquaculture, 2025, Vol.15, No.4, 184-196 http://www.aquapublisher.com/index.php/ija 193 changes in group structure are transmitted to the gonads through neuroendocrine signals. When a female fish becomes the dominant group, its brain undergoes neuroendocrine changes: cGnRH surges in the hypothalamus, and pineal AANAT (the enzyme that controls melatonin synthesis) activity is upregulated. Increased melatonin secretion is thought to inhibit female reproductive behavior in female fish, thereby releasing their maleization potential. Meanwhile, the rise of GnRH stimulates pituitary FSH secretion, which affects the expression of cyp19a1a and dmrt1 in the gonadal hormone axis, thereby completing the transmission from social signals to molecular gene expression. In addition, the nutritional state and metabolic environment may affect gonad cell proliferation by regulating the mTOR pathway, thereby changing the expression of certain genes in the gonad. A typical example is that in the early stages of sexual reversal, some heat shock protein genes (HSPs) are upregulated in response to changes in the cellular environment, which can be seen as a direct reflection of gene expression by environmental stress. As the reversal deepens, HSP expression decreases and is replaced by other differentiated genes, which shows that the environmental effect is mainly in the initial initiation stage, and subsequently the self-sustaining conversion process by the gene network (Chen et al., 2022). Figure 3 Induction of final maturation in females by pheromones released from mature males (Adopted from Soyano et al., 2022) 7 Construction and Analysis of Gender Regulation Network Model 7.1 Integration and visualization of gene regulation network map Given that grouper gender decision involves the synergy of multi-level and multi-factors, it is of great significance to establish a comprehensive regulatory network model. Integrating the aforementioned genes, hormones and environmental signals can draw a network map of grouper gender regulation. Through this integration, the decentralized regulatory relationship is presented as an overall network map, and the multi-factor interaction pattern of gender determination can be visually seen (Li and Xu, 2024). Some studies have been trying similar integrations: for example, a team conducted a genome-wide and multiomic comparison of female, primary and secondary grouper groups in oblique bands, and constructed a schematic diagram of the regulatory network of gender-related genes based on the data, highlighting the core position of the brain-pituitary-godal axis. Their results show that the axis connects the upstream environment and the downstream gonads, which plays a total scheduling role, and the key nodes of the molecular network such as Dmrt1, Foxl2, and Cyp19a1a determine the gonadal direction at the end of this axis (Nagarajan et al., 2013; Wu et al., 2023). 7.2 Multi-omics data-driven network modeling method In order to build a gender regulation network more comprehensively and objectively, integrating multi-omics data is a necessary means. Single transcriptome data reveals associations at the gene expression level, while protein interactions, apparent modifications, and phenotypic information all need to be included to reflect the real
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