Genome-Wide Identification and Expression Analysis of the BTB Gene Superfamily Provides Insight into Sex Determination and Early Gonadal Development of Alligator sinensis

The <i>BTB</i> gene superfamily is widely distributed among higher eukaryotes and plays a significant role in numerous biological processes. However, there is limited knowledge about the structure and function of <i>BTB</i> genes in the critically endangered species <i>Alligator sinensis</i>, which is endemic to China. A total of 170 <i>BTB</i> genes were identified from the <i>A. sinensis</i> genome, classified into 13 families, and unevenly distributed across 16 chromosomes. Analysis of gene duplication events yielded eight pairs of tandem duplication genes and six pairs of segmental duplication genes. Phylogenetics shows that the <i>AsBTB</i> genes are evolutionarily conserved. The cis-regulatory elements in the <i>AsBTB</i> family promoter region reveal their involvement in multiple biological processes. Protein interaction network analysis indicates that the protein interactions of the <i>AsBTB</i> genes are centered around CLU-3, mainly participating in the regulation of biological processes through the ubiquitination pathway. The expression profile and protein interaction network analysis of <i>AsBTB</i> genes during sex differentiation and early gonadal development indicate that <i>AsBTB</i> genes are widely expressed in this process and involves numerous genes and pathways for regulation. This study provides a basis for further investigation of the role of the <i>BTB</i> gene in sex differentiation and gonadal development in <i>A. sinensis</i>.