Sequencing And Analysis Of Complete Mitochondrial Genome Of Haliotis Ovina

Haliotis ovina is mainly distributed in South China Sea and Southeast Asia.It has high economic value in fishery and agriculture.In this paper,16Sr RNA,COI and COII genes of Haliotis ovina were amplified and sequenced.The genetic distance of 16Sr RNA,COI and COII genes and other abalone species were analyzed.The complete mitochondrial genome sequence of Haliotis ovina is obtained which enriches the diversity of abalone genetic information database in the world.It provides valuable basis for further study of abalone culture or even artificial hybridization in China.The main research results are shown as follows:（1）BLAST,genetic distance and phylogeny tree were used to investigate the feature of Haliotis ovina 16S r RNA gene.The results manifested that the mitochondrial 16Sr RNA gene sequence of Haliotis ovina was the most similar to that of Haliotis australis with a similarity of 93.66%.The second similarity is the mitochondrial 16Sr RNA of Haliotis midae,with a similarity of 93.29%.Other species like Haliotis tubeculata,Haliotis laevigata and Haliotis laevigata,were more than 90%similar to the mitochondrial 16Sr RNA of Haliotis ovina.The genetic distance between Haliotis diversicolor and Haliotis ovina is the closest,only 0.120.The genetic distance with Haliotis australis was the second one.Yet it was much larger than that of Haliotis diversicolor which was 1.187.In the phylogenetic tree of mitochondrial 16Sr RNA sequence of 16 abalone species,it can be seen that Haliotis diversicolor is same as Haliotis ovina,which is consistent with the result of genetic distance analysis.（2）BLAST,genetic distance and phylogeny tree were used to investigate the feature of Haliotis ovina COI gene.The results manifested that the mitochondrial COI gene sequence of abalone was the most similar to that of Haliotis laevigata,with a similarity of 85.21%.The second similarity is the mitochondrial CO I gene of Haliotis rubra,with a similarity of 84.82%.The genetic distance between Haliotis rubra and Haliotis ovina was the closest,only 0.198.Compared with Haliotis rufescens,the genetic distance between Haliotis rufescens and Haliotis ovina is 0.202 which is also pretty close.In the phylogenetic tree of 15 species of abalone,Haliotis ovina,Haliotis rubra and Haliotis laevigata are grouped together.（3）BLAST,genetic distance and phylogeny tree were used to investigate the feature of Haliotis ovina COII gene.The results manifested that the mitochondrial COII gene sequence of abalone was the most similar to that of Haliotis asinina,with a similarity of 85.47%.The second is the mitochondrial COII gene sequence of Haliotis iris,with a similarity of 82.46%.The genetic distance between Haliotis ovina and Haliotis laevigata is the closest compared with other 18 species.It is only 0.104.The genetic distance from Haliotis ovina to Haliotis varia was 1.115.It can be seen that Haliotis dissona and Haliotis varia are grouped together with Haliotis ovina among 19 abalone species.The total length of mitochondrial genome of Haliotis ovina is 16531bp.The total A+T content is59%while the G+C content is 41%which indicates A+T preference.The complete mitochondrial genome of Haliotis ovina consists of 37 genes,including 13 protein coding genes（PCGs）,2 r RNAs（12Sr RNA,16Sr RNA）and 22 t RNA genes.The genes encoding the protein include two ATP6,ATP8,one cytochrome b,three cytochrome c（COI-III）and seven NADH dehydrogenase subunits（ND1-6,ND4l）.Besidesr ND4,ND5 and ND6,the other 10 protein coding genes（PCGs）were all initiated by ATG.A total of 7 protein coding genes（PCGs）were terminated by TAG codon.ND3,COX 1,COX 2,ATP8 and ND1 genes were terminated by TAA codon.The BLAST results of the complete mitochondrial genome of Haliotis ovina manifested that the similarity of the complete mitochondrial genome of Haliotis rubra and Haliotis laevigata was the highest which is 83.29%and 82.64%,respectively.Multiple sequence alignment indicated that the complete mitochondrial genome of Haliotis ovina performs high repetitiveness with other major abalone species.The above analysis results manifested that the three main gene fragments 16Sr RNA,CO I and CO II,which are often used for genetic evolution analysis,are also relatively conservative for Haliotis ovina.Besides the close relationship between Haliotis ovina and Haliotis diversicolor.Haliotis rubra and Haliotis laevigata are also close to Haliotis ovina.After understanding the species of Haliotis ovina at the molecular level,we also pay attention to other factors that affect the growth and development of Haliotis ovina.In order to further explore the factors affecting the growth and development of Haliotis ovina,γ-aminobutyric acid,potassium chloride and 5-hydroxytryptamine were selected as the main chemical influencing factors for the experiment,and the corresponding conclusions were drawn:γ-aminobutyric acid can improve the survival rate,adhesion rate and metamorphosis rate.Potassium chloride can only induce attachment,but has no effect on larval survival and metamorphosis;5-hydroxytryptamine can induce attachment and metamorphosis,but has no effect or inhibition on larval survival.Therefore,the effect of 10^-4mol/L GABA is better,which can be used as an effective inducer in Haliotis ovina culturing.