Genetic Diversity of Taenia Hydatigena on the Qinghai-Tibetan Plateau

Abstract

Taenia hydatigena (T. hydatigena), a globally distributed parasite, poses a considerable economic burden on livestock industries. The species exhibits an atypical characteristic for tapeworms: a wide range of intermediate hosts. Consequently, a comprehensive analysis of the T. hydatigena mitochondrial genome is warranted. A phylogenetic tree was constructed via the maximum likelihood method, and the HKY model was employed for divergence time estimation. The complete mitochondrial genome of T. hydatigena was found to be 13490 bp in length, with a high AT content (71%) relative to CG content (29%). Collinearity analysis revealed predominantly forward matching and minimal gaps, suggesting genomic stability. A phylogenetic tree based on 12 protein-coding genes (PCGs) and the cytochrome oxidase subunit I (COI) gene confirmed that T. hydatigena belongs to the family Taeniidae. Divergence time analysis using COI data estimated that T. hydatigena diverged approximately 19.39 million years ago (Mya), a period coinciding with the transition from the MI-1 glacial period to a warmer climate. We hypothesize that the differentiation of T. hydatigena was driven by host differentiation resulting from environmental changes associated with this warming trend. Given the limited existing research on the T. hydatigena mitochondrial genome, this study contributes valuable empirical data to further evolutionary investigations of this parasite.