Comprehensive Genome-Wide Analysis of Dmrt Transcription Factors Reveals Their Roles in Sexual Dimorphism in Scolopendra mutilans

The double-sex and mab-3-related transcription factors (Dmrt) are widely distributed in the animal kingdom and play a crucial role in sex determination and differentiation. In this study, we identified eight Dmrt transcription factors in the genome of the centipede <i>Scolopendra mutilans</i>, including five <i>Dsx</i>-related genes (as <i>Dsx1</i>, <i>Dsx2</i> (five splice variants), <i>Dsx3</i>, <i>Dsx4</i> and <i>Dsx5</i>) and three <i>Dmrt</i>-related genes (as <i>Dmrt11E</i>, <i>Dmrt99B</i>, and <i>Dmrt93B</i>). Phylogenetic analysis revealed evolutionary conservation across arthropods, with <i>Dsx</i> genes clustered into class-specific clades (Chilopoda, Insecta, Crustacea, Arachnida). Structural analysis confirmed conserved DM domains and sex-specific motifs, with tandem duplication of <i>Dsx2</i> on chromosome 4. Expression profiling demonstrated significant sexual dimorphism: <i>Dsx5</i> was female-biased, whereas <i>Dsx2</i>, <i>Dsx3</i>, and <i>Dsx4</i> were male-biased, suggesting their functional divergence in sexual differentiation. Correlation analysis linked the expression of <i>Sxl</i> and <i>Fem-1C</i> to the regulation of <i>Dsx</i> isoforms, suggesting the presence of a conserved upstream regulatory cascade for sex-specific splicing. These findings elucidate the structural and functional landscape of <i>Dmrt</i>s in <i>S. mutilans</i>, and provide insights into how sex-determination mechanisms evolved in Myriapoda.