The mitochondrial genome of striped snakehead Channa striata (Perciformes: Channidae) and phylogenetic analysis.

The complete mitochondrial genome of Channa striata was determined using NGS technologies. It had a double-stranded DNA molecule with the length of 16,531 bp and was made up 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and one control region. The gene content and arrangement were typical for teleost mtDNA. The molecular data here we presented could play a useful role to study the evolutionary relationships and population genetics of Channa striata.

The striped snakehead Channa striata, has a wide range of habitats ranging from rivers, swamps, ponds, canals, lakes, and the land of rice fields (Song et al. 2013). Their natural populations are extensively distributed across southern Asia, Yunnan Province of China, Indochina, and Sunda Islands (Mohsin and Ambak 1983; Lee and Ng 1994). This carnivore species is able to tolerate adverse environments due to its hardiness and air-breathing capabilities assisted with a suprabranchial chamber, an air-breathing organ (Chandra and Banerjee 2004). Due to its commercial value, agreeable flavor local food, it has become an important freshwater aquaculture species in South China and Thailand (Hossain et al. 2008). It is also one of the most suitable channa species for aquarium due to its beautiful colouration. However, it has been an invasive species in South China. Escaped fish from aquaculture has caused huge impact on local river ecosystem because of its predatory nature and voracious appetite in South China.To facilitate the future researches of taxonomic resolution and population genetics, the complete mitochondrial genome of C. striata was sequenced and characterized in the present study (GenBank accession number MN205549).

The samples were collected from Haikou, Hainan Province of China (19°37′56.28″N, 110°25′21.29″E). After sampling, the specimens were stored in 90% ethanol and kept in Freshwater Fisheries Research Institute of Jiangsu Province (JSFFRI-19117). Thirty pairs of PCR primers were designed based on sequences from related fish C. argus (GenBank number GU937112) and C. gachua (GenBank number MK371068, Zhou et al. 2019). Mitogenome database was annotated by DOGMA (Wyman et al. 2004) and MitoFish (Iwasaki et al. 2013).

The complete mitochondrial genome of C. striata was 16,531 bp in length, which composed of 13 protein-coding genes (PCG), 22 tRNA, 2 rRNA genes and one control region. All the genes of C. striata encoded on the H-strand with the exception of one PCG (ND6) and 8 tRNAs (tRNA-Gln, tRNA-Ala, tRNA-Asn, tRNA-Cys, tRNA-Tyr, tRNA-Ser(UCN), tRNA-Pro, and tRNA-Glu), which was typical for teleost mtDNA (Zhong et al. 2018). The typical ATG start codons were present in PCGs except for COI with GTG, and three types of stop codons (TAA, TA–, and T–) were found, and the incomplete stop codons were presumably completed by posttranscriptional polyadenylation (Ojala et al. 1981). The overall nucleotide composition is 29.0% for A, 26.1 for T, 29.0 for C and 15.9% for G, with a slight AT bias of 55.1% and a strong bias against G.

The cytochrome c oxidase subunit I (COI) sequence of C. striata and other 14 closely related species were used for phylogenetic analysis by the neighbor-joining method with MEGA 6.06 (Tamura et al. 2013). Different species from the same family clustered together (e.g. Channidae and Osphronemidae). Channa striata clustered together with other snakehead fishes forming the genera Channa (Figure 1).

Figure 1.

The phylogenetic relationship of C. striata with the other species using NJ method with 1000 bootstrap replicates. The bootstrap values for the NJ analysis are shown on the nodes.