title: Mitogenomic perspectives on the origin of Tibetan loaches and their adaptation to high altitude.
abstract: Tibetan loaches are the largest group of Tibetan fishes and are well adapted to the Tibetan Plateau. To investigate the origin of Tibetan loaches and their adaptations to the Tibetan Plateau, we determined 32 complete mitochondrial genomes that included 29 Tibetan loach species, two Barbatula species and Schistura longus. By combining these newly determined sequences with other previously published mitochondrial genomes, we assembled a large mitogenomic data set (11,433 bp) of 96 species in the superfamily Cobitoidea, to investigate the phylogenetic status of the genus Triplophysa. The resulting phylogeny strongly supported that the genus Triplophysa forms a monophyletic group within Nemacheilidae. Our molecular dating time suggests that the lineage leading to the Tibetan loaches and other loaches diverged approximately 23.5 Ma, which falls within the period of recent major uplifts of the Tibetan Plateau in the Early Miocene. Selection analyses revealed that the mitochondrial protein-coding genes of Tibetan loaches have larger ratios of nonsynonymous to synonymous substitutions than do those of non-Tibetan loaches, indicating that Tibetan loaches accumulated more nonsynonymous mutations than non-Tibetan loaches and exhibited rapid evolution. Two positively selected sites were identified in the ATP8 and ND1 genes.
authors.affiliation: The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, PR China.|University of the Chinese Academy of Sciences, Beijing 100049, PR China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.affiliation: The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, PR China.|University of the Chinese Academy of Sciences, Beijing 100049, PR China.
authors.forename: Yanjun
authors.initials: Y
authors.lastname: Shen
authors.affiliation: University of the Chinese Academy of Sciences, Beijing 100049, PR China.|Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810001, China.
authors.forename: Chenguang
authors.initials: C
authors.lastname: Feng
authors.affiliation: Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810001, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Zhao
authors.affiliation: Sichuan Key Laboratory of Conservation Biology on Endangered Wildlife, College of Life Sciences, Sichuan University, Chengdu 610065, PR China.
authors.forename: Zhaobin
authors.initials: Z
authors.lastname: Song
authors.affiliation: Gansu Key Laboratory of Cold Water Fishes Germplasm Resources and Genetics Breeding, Gansu Fishers Research Institute, Lanzhou 730030, PR China.
authors.forename: Yanping
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, PR China.
authors.forename: Liandong
authors.initials: L
authors.lastname: Yang
authors.affiliation: The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, PR China.
authors.forename: Shunping
authors.initials: S
authors.lastname: He
mesh_terms: D000064:Acclimatization / Q000235:genetics*; D000531:Altitude; D000818:Animals; D003531:Cypriniformes / Q000145:classification / Q000235:genetics*; D004272:DNA, Mitochondrial / Q000737:chemistry / Q000235:genetics; D019143:Evolution, Molecular; D050259:Genes, Mitochondrial / Q000235:genetics; D054629:Genome, Mitochondrial / Q000235:genetics*; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D018609:Tibet
chemical_list: D004272:DNA, Mitochondrial