Complete Mitochondrial Genome Sequencing of Asian Glass Lizards (Anguidae: Dopasia): Comparative Analysis With Limbless Anguids and New Insights Into the Adaptive Evolution of Protein-Coding Genes.

The mitochondrial genome (mitogenome) plays a critical role in energy production and is frequently subject to positive selection due to its impact on adaptive evolution. In this study, we investigated positive selection pressures in the mitogenomes of Dopasia (Anguidae), a genus that occupies diverse habitats. Using next-generation sequencing, we determined the complete mitogenomes of eight individuals (six D. gracilis and two D. harti) and compared them with 28 published mitogenomes of the Anguidae family from GenBank. Although purifying selection is the predominant evolutionary force, six of the 13 protein-coding genes showed signatures of positive selection. Notably, amino acid preferences at these sites correlated with the geographic distributions of the species, suggesting the involvement of the mitogenome in environmental adaptation. We also mapped these sites onto three-dimensional protein structures and transmembrane domains. Phylogenetic analyses resolved Dopasia's relationship with other Anguidae species, but challenged the monophyly of D. hainanensis within the genus. Our findings highlight the potential role of the mitogenome in ecological adaptation and underscore the need for a broader sampling of Anguidae mitogenomes to clarify evolutionary mechanisms.