Complete mitochondrial genome sequence of Pareuchiloglanis kamengensis in the Yarlung Zangbo River, Tibet.

Pareuchiloglanis kamengensis belongs to the family of Sisoridae, Pareuchiloglanis. It is distributed in the Yarlung Zangbo River, the Irrawaddy River, the Nujiang River, and the Lancang River in southwestern China. In this study, we first published the complete mitochondrial genome sequence of Pareuchiloglanis kamengensis, which was 16,589 bp in length. This genome consists of 13 protein-coding genes (PCGs), 22 tRNA genes, two rRNA genes, and a non-coding A + T-rich region. The PCGs start with a traditional ATG except for COX1 and NAD3, which start with GTG and ATA instead, respectively, and end with stop codon TAA, TAG, TA, or a single T base. All tRNA have the typical clover-leaf structure. The phylogenetic tree of the whole mitogenome sequence is constructed by using neighbor-joining (NJ) method and the phylogenetic relationship among the family Sisoridae is further analyzed. We except to provide the theoretical basis for the further study of the phylogenetic relationship, taxonomic status, and conservation and management of genetic resources of Sisoridae catfishes.

Introduction

Pareuchiloglanis kamengensis belongs to Sisoridae, Pareuchiloglanis, and is distributed in the Yarlung Zangbo River, the Irrawaddy River, the Nujiang River and the Lancang River in southwestern China. In Tibet, it is mainly distributed in the lower reaches of the Yarlung Zangbo River (Wu et al. 1981). In this study, P. kamengensis were collected from the Motuo section (29.18°N, 94.16°E) and were stored in the fish specimen room of Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences (specimen Accession number: XZ-1-001). We first published the complete mitochondrial genome of P. kamengensis and then analyzed the whole mitochondrial genome sequence.

The complete mitochondrial genome of P. kamengensis is a typical circular molecular of 16,589 bp in length and is deposited in GenBank (accession number: MN396886). It contains the typical set of 37 mitochondrial genes, including 13 protein-coding genes (PCGs), 22 tRNA, 2 rRNAs, and an A + T-rich region. The PCGs, tRNA gene, rRNA gene, and an A + T-rich region account for 69.56, 9.40, 15.98, and 5.38%, respectively. Among the 37 genes, tRNA-Gln, tRNA-Ala, tRNA-Asn, tRNA-Cys, tRNA-Tyr, tRNA-Ser, tRNA-Glu, tRNA-Pro, and NAD6 genes are encoded in the H-chain, and the rest are in L-Chain coding. Thirteen PCGs of P. kamengensis contain three start codons (GTG, ATA, and GTG), except that the COX1 and NAD3 genes use GTG and ATA as the start codons, respectively, and all other PCGs use ATG as the start codon. There are four stop codons (TAA, TAG, TA-, and T–), in which TAG is the stop codon of NAD1, COX1, and NAD6 genes. TAA is the stop codon of NAD1, ATP8, ATP6, NAD4L, and NAD5 genes. COX3 gene uses incomplete TA as a stop codon. COX2, NAD3, NAD4, and Cyt b genes use incomplete T as a stop codon. There are one or two nucleotides folding between two pairs of adjacent tRNAs in P. kamengensis tRNA genes (such as tRNA-IL and tRNA-Gln, tRNA-Thr and tRNA-Pro), which is also found in other catfishes (Lee et al. 2001). In this study, all 22 tRNA genes of P. kamengensis form the typical clover-leaf structure.

In this study, Cranoglanis bouderius and Pangasianodon gigas are used as outgroups to build the phylogenetic tree of the whole mitogenome sequence by using the neighbor-joining (NJ) method (Figure 1). The monosyllabicity of Sisoridae catfishes is supported. The P. kamengensis in this study and the other three selected Pareuchiloglanis fishes also form a monophyletic group, which is consistent with Yu’s research results (Yu and He 2012). In addition, Pseudecheneis fishes have always been regarded as a group with an uncertain phylogenetic position in the study of Sisoridae catfishes. The results of this study show that the phylogenetic position of Pseudecheneis fishes is in the interior of the glyptosternoid fishes, which is consistent with the results of He (He 1996) and Guo et al (Guo et al. 2005, 2007).

Figure 1.

The phylogenetic tree (neighbor-joining) of Pareuchiloglanis kamengensis in this study and other 16 species based on the whole mitogenome sequence. Shown next to the nodes are bootstrap support values based on 1000 replicates.