The Complete Mitochondrial DNA Of Channa Argus,channa Maculata And Their Hybrids(C.maculata♀×C.argus♂and C.argus♀×C.maculata♂):Genome Sequence Analysis And Identification Of Hybrids

The northern snakehead(Channa argus) and blotched snakehead(Channa maculata) are very important, being native fish species in our country. They belong to Perciformes, Channoidei, Channidae, Channa. The northern snakehead and blotched snakehead have high fillet yield and taste delicious. Their meat is fine quality and high nutritional value for food, so they are deeply welcome by people in China and Southeast Asian countries. Their environmental requirements are lower than some commen fishes. They have strong ability to adapt the environment and can achieve high density cultivation. The snakehead fishes in the aquaculture industry are more and more important. In the production practice, The northern snakehead and blotched snakehead hybridized getting two hybrids (blotched snakehead♀×northern snakehead♂and northern snakehead♀×blotched snakehead♂) were exploited. Hybrids exhibited good heterosis in farming. Because the profit of hybrids’cultivating has excellent performance, farmers are more willing to choose the hybrids’cultivating. Now, the hybrids accounted for the main amount of the cultivating, becoming the main farming species.The hybrids show better characters than their parents in practice, and there are also differences in growth between the two hybrids. The oxygen consumption rate and asphyxiant point are closely related to the survival and growth of fish, so the northern snakehead and blotched snakehead and two hybrids (blotched snakehead♀×northern snakehead♂and northern snakehead♀×blotched snakehead♂) from the oxygen consumption rate and asphyxiant points were studied preliminarily.The results showed that oxygen consumption rates of the northern snakehead, blotched snakehead, blotched snakehead♀×northern snakehead♂and northern snakehead♀ blotched snakehead♂were0.22mg/g·h,0.16mg/g·h,0.19mg/g·h and0.17mg/g-h respectively at one day-night (the average water temperture was25.1℃), and the suffocation concentrations were2.47mg/L,1.45mg/L,1.18mg/Land2.01mg/L respectively. The oxygen consumption rate and the suffocation points of those four kinds of fish were compared and analysised. The low asphyxiant points were also discussed. Hopefully, the results presented in this report would be beneficial to Channa aquaculture practice in China.Then, the mitochondrial DNA (mitochondrial DNA, mtDNA) about the northern snakehead, blotched snakehead, blotched snakehead♀×northern snakehead♂and northern snakehead♀×blotched snakehead♂were compared, providing the basic data for the germplasm resource protecting and utilization of the fish in Channidae.11pairs of primers were designed to cover the mitochondrial DNA of4species of fish and the complete mitochondrial sequences were amplified by PCR. Manual correction and mosaic after sequencing, we got the complet mitochondrial genome sequences from4species. Analysis the structure of mtDNA from4species, we positioned the positions and determine the size of each gene. The differences of mtDNA among the4species were distinguished. And the phylogenetic tree were constructed based on the nucleotide sequences of12protein-coding genes in the mitochondrial genome, using the methods of Bayesian inference and maximum likelihood.The phylogenetic position of the northern snakehead blotched snakehead were located. Suborder Channidae and Suborder Gobioidei gathered a branch, this showed a close genetic relationship. This also provided some data to support for the phylogenetic position of Suborder Channidae in Perciformes.Then15pairs of primers by analysing the differrences among the4kinds of fish were designed.15pairs of primers with the mitochondrial DNAs of the the northern snakehead and blotched snakehead and their hybrids were amplified. Among the primers, we got a special banding with the primers BY14which can distinguish the hybrids (blotched snakehead♀×northern snakehead♂and northern snakehead♀blotched snakehead♂). The length of this special sequence is201bp, using this molecular mark based on mitochondrial genomes the snakehead and blotched snakehead and their hybrids can be identified.