Functional Annotation and Comparative Analysis of Cytochrome P450 Protein Family Genes in Nine Chironomidae Species

Cytochrome P450 monooxygenases (P450s) are one of the most widespread enzyme superfamilies in the biological world. In insects, P450 proteins play a crucial role in the synthesis of endogenous substances and the metabolism of xenobiotics. To date, extensive research has been conducted on P450 gene-mediated detoxification and metabolism across multiple insect species. While Chironomidae species-dominant benthic organisms inhabiting diverse ecological niches and playing critical ecological roles-remain largely uncharacterized in terms of P450 protein annotation, with the exception of a single study on <i>Propsilocerus akamusi</i>. In this study, we expanded the annotation scope by identifying the P450 protein genes in eight additional Chironomidae species. A total of 577 P450 protein genes were annotated across the eight species, which could be classified into the following four distinct clans: 50 belonging to the CYP2 clan, 258 to the CYP3 clan, 198 to the CYP4 clan, and 71 to the Mito clan. Phylogenetic analysis using <i>Drosophila melanogaster</i> as an outgroup revealed that the CYP2 clan and the Mito clan are highly conserved during evolution, while the CYP3 clan and the CYP4 clan have undergone significant expansion. Most P450 proteins in Chironomidae species exhibit clear orthologous relationships with their <i>D. melanogaster</i> counterparts. Our research contributes to a better understanding of the evolutionary processes and the physiological functions of P450 proteins in Chironomidae species and lays the foundation for elucidating the role of P450 in environmental adaptability among the Chironomidae species inhabiting diverse habitats.