The complete mitochondrial genome of Amur bitterling (Rhodeus sericeus) from China

The complete mitogenome of Paratanakia chii (Cypriniformes; Cyprinidae)

Paratanakia chii is a bitterling fish of the genus Paratanakia, subfamily Acheilognathinae and family Cyprinidae. The mitochondrial DNA sequence of P. chii is reported in this paper. The complete mitochondrial genome of P. chii is 16,575 bp in length, including 13 protein-coding genes (PCGs), 2 rRNA genes, 22 tRNA genes, and 1 displacement loop (D-loop). The genome sequence is consistent with those of most other carp. The majority of PCGs have AT- (Met) start codons and TA- end codons. The A + T contents of the genome, PCGs, transfer RNAs (tRNAs), and ribosomal RNAs (rRNAs) are 56.92%, 58.07%, 56.34%, and 54.21%, respectively. Phylogenetic analysis showed that P. chii is most closely related to Tanankia himantegus. These data will benefit relative ecological and phylogenetic studies.

Phylogeographical Analysis of the Freshwater Gudgeon Huigobio chenhsienensis (Cypriniformes: Gobionidae) in Southern China

The freshwater gudgeon Huigobio chenhsienensis (Cypriniformes: Gobionidae) is a small fish endemic to southern China. In this study, we used mitochondrial cytochrome b gene (Cytb), from wide-ranging samplings of H. chenhsienensis from the Ou River (the central of southern China) to the Yangtze River Basin (the northernmost part of southern China) to explore genetic variations and the evolutionary history of H. chenhsienensis in southern China. In total, 66 haplotypes were identified from Cytb sequences of 142 H. chenhsienensis individuals, which could be divided into lineages A, B, and C with divergence times of ~4.24 Ma and ~3.03 Ma. Lineage A was distributed in the lower reaches of the Yangtze River, the Oujiang River, and the Jiao River, lineage B was distributed in the Qiantang River and the Cao'e River, whereas lineage C was restricted to the Poyang Lake drainage from the middle reaches of the Yangtze River. Lineage A could be subdivided into sub-lineages A-I, A-II, A-III, and A-IV, with divergence times of 1.30, 0.97, and 0.44 Ma. Lineage C could be subdivided into sub-lineages C-I and C-II, with a divergence time of 0.85 Ma. Our findings indicate that climate change during the Pliocene and Pleistocene eras, as well as the limited dispersal ability of H. chenhsienensis, have been major drivers for shaping the phylogeographical patterns of H. chenhsienensis.

Complete mitochondrial genome of Rhodeus cyanorostris (Teleostei, Cyprinidae): characterization and phylogenetic analysis

Rhodeuscyanorostris Li, Liao & Arai, 2020 is a freshwater fish that is endemic to China and restricted to Chengdu City in Sichuan Province. This study is the first to sequence and characterize the complete mitochondrial genome of R.cyanorostris. The mitogenome of R.cyanorostris is 16580 bp in length, including 13 protein-coding genes, two rRNA genes, 22 tRNA genes, and a control region (D-loop). The base composition of the sequence is 28.5% A, 27.6% C, 26.4% T, and 17.5% G, with a bias toward A+T. The genome structure, nucleotide composition, and codon usage of the mitogenome of R.cyanorostris are consistent with those of other species of Rhodeus. To verify the molecular phylogeny of the genus Rhodeus, we provide new insights to better understand the taxonomic status of R.cyanorostris. The phylogenetic trees present four major clades based on 19 mitogenomic sequences from 16 Rhodeus species. Rhodeuscyanorostris exhibits the closest phylogenetic relationship with R.pseudosericeus, R.amarus, and R.sericeus. This study discloses the complete mitochondrial genome sequence of R.cyanorostris for the first time and provides the most comprehensive phylogenetic reconstruction of the genus Rhodeus based on whole mitochondrial genome sequences. The information obtained in this study will provide new insights for conservation, phylogenetic analysis, and evolutionary biology research.

Complete mitochondrial genome of endangered Rhodeus pseudosericeus and its implications for the reconstruction of phylogenetic relationship among Acheilognathinae species

Rhodeus pseudosericeus is a native bitterling to the Korean Peninsula and found in very limited areas with small census size. Here, its complete mitochondrial genome was analyzed to provide novel data for the reconstruction of phylogenetic relationship among Acheilognathinae species. The genome was a 16,574 bp long consisting of 1 putative control region, 2 rRNA genes, 22 tRNA and 13 protein-coding genes. The gene arrangement was completely identical to those observed in other Acheilognathinae species as well as in other cyprinid species. In our phylogenetic analyses, three major genera of Acheilognathinae indepedently formed monophyletic groups in the tree reconstructed based on the whole genome sequences, whereas Rhodeus was not recovered as a single monophyly when solely considering protein-coding genes, indicating that the taxonomic reevaluation is still required in this subfamily.