Abstract: The Chinese sturgeon (Acipenser sinensis), a critically endangered Chondrostean fish, serves as a key model for understanding vertebrate genome evolution due to its unique lineage-specific whole-genome duplication (As3R), distinct from the teleost-specific Ts3R event. Despite the critical role of vitellogenin (Vtg) in ovarian maturation, the vtg gene family remains poorly characterized in sturgeons. Here, we performed a genome-wide identification and comprehensive analysis of vtg genes in A. sinensis. Three vtg genes (vtgAB1, vtgAB2a, and vtgAB2b) were identified and characterized in terms of genomic organization, conserved protein domains, and phylogenetic relationships. All three Vtgs exhibited complete domain architectures and conserved estrogen-responsive elements in their promoter regions. Phylogenetic reconstruction revealed clear orthology groups within Acipenseriformes and highlighted the basal position of sturgeon Vtgs relative to teleosts. Spatial and temporal expression profiling confirmed the exclusive hepatic origin of all Vtgs with specific transcription in hepatocytes. The study provides the first systematic molecular characterization of the vtgs in A. sinensis, offering valuable insights into the evolutionary diversification of Vtgs following sturgeon-specific genome duplication and establishing a foundation for improving artificial reproduction protocols for this endangered species.

Chinese Sturgeon; Vitellogenin; Gene Family; Genome-wide Identification; Phylogeny