Key Events in the Process of Sex Determination and Differentiation in Early Chicken Embryos.

Clarifying the intricate mechanisms underlying sex determination and differentiation regulation in chickens holds significant potential for advancing chicken sex control technologies. This endeavor not only augments fundamental research in developmental biology but also bolsters the economic viability of the poultry industry. Our investigation delved into the sex determination and differen-tiation molecular underpinnings of these processes during the early stages of chicken embryonic development E0 d blastocysts, E3.5-E6.5 d genital ridges, and E18.5 d gonads, leveraging high-throughput sequencing technologies. Isolate ESC and CEF cells to verify roles of glycolysis, histone acetylation, and DNA methylation in sex determination. Treat E18.5 d gonads with gly-colytic activators (SB431542 and PD0325901, 2i), DNA demethylation activators (Vitamin C, VC), or inhibitors of histone acetylation modification (Valproic Acid, VPA) and analyze gender related gene expression, hormone levels, and gonad morphology. Key findings revealed that sex differences emerged as early as the blastocyst stage, intensifying with embryonic development and marked by a surge in sexually dimorphic gene expression. GO and KEGG analyses highlighted the pivotal roles of energy metabolism and epigenetic modification process during this critical period. 2i, VC, or VPA interventions targeting E18.5 embryo gonads, induced a remarkable transformation of ovarian tissue into a testis-like structure, characterized by cortical thinning, medulla densification, down-regulation of female-specific genes (Foxl2, Wnt4), upregulation of male-specific genes (Sox9, AMH), and increased testosterone secretion. This phenotypic and molecular shift underscores the ability of metabolic and epigenetic modulators to reprogram ovarian development towards a male-like pat-tern, preserving male sexual characteristics. Collectively, our findings underscore the fundamental importance of energy metabolism and epigenetic modifications in orchestrating sex determination and differentiation during early chicken embryonic development. This work lays a solid foundation for future endeavors aimed at unraveling the intricate regulatory networks governing these vital processes in chickens.