Abstract
Triplophysa tibetana belongs to the family Cobitidae, which is popular in Tibet. We first published the complete mitochondrial genome of T. tibetana. The mitogenome sequence was 16,607bp long and composed of 13 protein-coding genes, 22tRNA genes, and 2 rRNA genes. The protein-coding genes started with a traditional ATG except for COX1, which started with one infrequent GTG instead, and terminated with stop codons TAA, TGG, TGA, or a single T— base. The overall GC content is lower than AT. We constructed the phylogenetic tree to verify the accuracy and utility of newly determined mitogenome sequences using the full mitogenome-related evolution events.
Triplophysa tibetana belongs to the family Cobitidae, found in Brahmaputra River, Lhasa River, Shiquan River and other riversabundantly in Tibet. People know little about it. In this study, Triplophysa tibetana was collected from the Lhasa River (sampling station geospatial coordinates is 29.66°N, 91.23°E), Tibet Province, China. This is the first study to publish the complete mitochondrial genome of T. tibetana. The total genomic DNA was extracted with the phenol-chloroform method (Taggart et al. Citation1992). The specimen was stored in the fish herbarium of Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences.
The complete mitochondrial genome of T. tibetana was 16,607bp and had been provided in GeneBank (accession no. KT122845). It consisted of 13 protein-coding genes, 2 rRNA genes, and 22tRNA. The arrangement of all genes was identical to other cobitidae species known to us, e.g. Rhodeus lighti (Li et al. Citation2015), but it excluded non-coding regions. The gene composition and order were similar to most of the other teleosts. Intriguingly, only COX1 gene used GTG as a start codon, but other protein-coding genes used ATG as the start codon. There were three stop codons (TGG, TAA, and TGA) and incomplete stop codon (T––) in the protein-coding genes. The 22tRNA genes were identified using the program tRNAscan-SE 1.21 (http://lowelab.ucsc.edu/tRNAscan-SE/). The overall base composition was A (28.03%), T (27.64%), G (18.46%), C (25.87%), and an AT bias of 55.67%, as generally reported in other teleosts mitochondrial genomes. The two rRNA genes were 576bp (12SrRNA) and 1687bp (16SrRNA).
shows the phylogenetic tree of T. tibetana obtained in this study and other 10 species of Cypriniformes for which mitogenome sequence have been reported (software: ClustalX 1.81 and Mega 4.0). Triplophysa tibetana is not closely related to other species and is similar to Spinibarbus, but not close. To our knowledge, it was is not published earlier and this study reports the first sequence. In addition, it will further enrich the knowledge on the species belonging to the family Cobitidae.
Figure 1. The phylogenetic tree of T. tibetana in this study and other 10 species of Cypriniformes, which have reported mitogenome sequence.
Acknowledgements
The authors would like to thank Special economic project of agricultural public industry research (utilization and protection of fish resources in Yarlung Zangbo River) and Special Financial Funds of the Ministry of Agriculture and Rural Affairs (investigation on fish resources and environment in key waters of Tibet).
Disclosure statement
The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.
Additional information
Funding
References
- Li CH, Jin SG, Dong YL, Wang L, Shi WY. 2015. The complete mitochondrial genome of Rhodeus lighti (Cypriniformes:Cyprinidae): sequencing and analysis. Mitochondrial DNA A. 27:2298–2299.
- Taggart JB, Hynes RA, Prodouhl PA, Ferguson A. 1992. A simplified protocol for routine total DNA isolation from salmonid fishes. J Fish Biol. 40:963–965.