The complete mitochondrial genome sequence of Triplophysa anterodorsalis (Teleostei, Balitoridae, Nemacheilinae)

A Comprehensive Analysis of Triplophysa labiata (Kessler, 1874) Mitogenome and Its Phylogenetic Implications within the Triplophysa Genus

In order to resolve the long-standing controversy surrounding the relationships within the Triplophysa genus, we conducted an extensive analysis of the complete mitogenome of Triplophysa labiata using DNBSEQ short reads. Additionally, we reconstructed the phylogeny of the Nemacheilidae family using mitogenome data. By comparing all available mitogenomes within the Triplophysa genus, we gained valuable insights into its evolutionary history. Our findings revealed that the mitogenome sequence of T. labiata is circular, spanning a length of 16,573 bp. It encompasses 13 protein-coding genes (PCGs), 22 transfer RNAs (tRNAs), 2 ribosomal RNAs (rRNAs), and a control region (D-loop). Among the PCGs, the start codon ATG was commonly observed, except in cox1, while the stop codons TAA/TAG/T were found in all PCGs. Furthermore, purifying selection was evident across all PCGs. Utilizing maximum likelihood (ML) methods, we employed the 13 PCGs and the concatenated nucleotide sequences of 30 Triplophysa mitogenomes to infer the phylogeny. Our results strongly supported the division of the Triplophysa genus into four primary clades. Notably, our study provides the first evidence of the close relationship between T. labiata and T. dorsalis. These findings serve as a significant foundation for future investigations into the mitogenomics and phylogeny of Nemacheilidae fishes, paving the way for further advancements in this field of research.

Complete Mitogenome of the Triplophysa bombifrons: Comparative Analysis and Phylogenetic Relationships among the Members of Triplophysa

In the last decade, the phylogenetic relationships within the genus Triplophysa have become controversial, due to a lack of molecular data. The mitochondrial genome plays a vital role in the reconstruction of phylogenetic relationships and in revealing the molecular evolution of bony fishes. Herein, we obtained the complete mitogenome of Triplophysa bombifrons via HiFi reads of the Pacbio Sequel II system and DNBSEQ short-reads. We compared all available mitogenomes of the Triplophysa genus and reconstructed the phylogeny of Nemacheilidae, based on the mitogenomes, using maximum likelihood (ML) methods. The results show that the complete mitogenome sequence of T. bombifrons was circular and 16,568 bp in length, including 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA), 2 ribosomal RNA (rRNA), and a typical control region (D-loop). The most common start codons were ATG, except for cox1, and TAA/TAG were the stop codons for all PCGs. In total, 677 SNPs and 9 INDELs have been found by comparing the sequence divergence between this study and previous reports. Purity selection was found in all PCGs. Phylogeny was inferred by analyzing the 13 PCGs and the concatenated nucleotide sequences of 30 mitogenomes. The phylogenetic analyses based on the nucleotides of the 13 PCGs supported the assumption that the Triplophysa genus can be divided into 4 main clades and demonstrated that T. bombifrons and T. tenuis are closely related species for the first time. This study laid the foundation for further study on the mitogenome and phylogeny of Nemacheilidae fishes.

Complete mitochondrial genome of Triplophysa bleekeri (Cypriniformes: Balitoridae: Nemacheilinae), and analysis of mitochondrial genetic variability among Triplophysa species

The complete mitochondrial genome of the stone loach Triplophysa bleekeri collected from the Anning River, a tributary of the Yalong River, in Sichuan Province was sequenced. The genome is 16,573 bp in length, consisting of 13 protein-coding genes, 22 transfer RNA (tRNA) genes, two ribosomal RNA (rRNA) genes, and a noncoding control region. Most of the genes are encoded on the heavy strand, except for ND6 and eight tRNAs. The overall base composition of T. bleekeri is 28.1% for A, 28.4% for T, 25.5% for C, 18.0% for G, with a slight A+T bias of 56.5%. The complete mitochondrial genetic variability is high among different Triplophysa species and between the two T. bleekeri individuals from different rivers.

Characterization of the complete mitochondrial genome sequence of Homatula potanini (Cypriniformes, Nemacheilidae, Nemachilinae)

Homatula potanini is an endemic and one of ornamental fishes in the upper stream of the Yangtze River and its tributaries. However, wild populations of H. potanini declined sharply due to anthropological activity in the Jinsha River during the past decades. In present study, the complete mitochondrial DNA genome sequence of H. potanini was first determined by DNA sequencing based on the PCR fragments. The complete mitochondrial genome sequence is a circular molecule of 16,569 bp in size. It consists of 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and a control region (D-loop). The gene nucleotide composition of H. potanini is 30.1% A, 26.9% C, 16.7% G, and 26.3% T, with a relatively high A + T content (56.4%). The results could provide useful data for studies on genetic structure and rational resource conservation in H. potanini.