Researches On Mitochondrial Coding Region Of Haliotis Discus Hannai Ino And Haliotis Diversicolor Reeve

H. discus hannai Ino and H. diversicolor Reeve belong to Gastropoda, Prosobranch, Archaeogastropoda, Haliotidae, Haliotis. Their coding regions of mitochondrial genome have been researched. We investigated the sequences and variable nucleotide sites of coding regions of mitochondrial genome in order to find out the distribution and quantity of SNPs in coding region of mitochondrial genome of H.discus hannai Ino, and to find out the features of coding region of mitochondrial genome of H. diversicolor Reeve.1. Research on single nucleotide polymorphism(SNP) distributing in coding region of mitochondrial genome of Pacific abalone Haliotis discus hannai InoSampling from China and Japan, sixteen individuals' coding region of mitochondrial genomes of Pacific abalone Haliotis discus hannai Ino were sequenced in this study.370 Single Nucleotide Polymorphisms(SNPs) were found out of these sequences from 15914bp to 15916bp in length. Twenty-five amino acid residues are replaced owing to Twenty-six SNPs. According to distribution of SNPs in protein-coding genes we elicit that genes coding for the NADH complex is fast evolving, whereas genes for cytochrome c oxidase complex and cytochrome b apoenzyme are more conserved. Twenty-five SNPs differential in populations were gained in this study, some of them may be developmental for research of Molecular Markers identifying different populations of Pacific abalone Haliotis discus hannai Ino.2. Research on coding region of mitochondrial genome of Haliotis diversicolor ReeveThe coding region of mitochondrial genomes of the small abalone Haliotis diversicolor Reeve,15863bp in length, was sequenced in this research. The sequence contains 13 protein-coding genes,2 ribosomal RNAs, and 21 transfer RNAs found in other metazoan mtDNA. The H. diversicolor mtDNA gene order is novel, separated from the black chiton Katharina tunicata by the individual translocations of 4 tRNAs and reversion of trnP. Moreover, H. diversicolor and many species of Apogastropoda, all of which belong to Orthogastropoda, put up with distinct feature in gene order. To detect the influence of selection pressure in Haliotis, the numbers of Ka and Ks were calculated and their ratios have been plotted for comparisons. It suggests a relaxation of purifying selection in the nad2, nad4L, nad6 and atp8 genes compared with the more conservative genes such as coxl, cox2 and cob.The coding regions of mitochondrial genome of two other individuals of H. diversicolor were also sequenced and compared in the study.114 variable nucleotide sites were found in mtDNA genome of the three individuals, and most of the variable sites don't change the amino acid coded by mtDNA. The research suggests that mitochondrial genome can be used for identification of different populations in H. diversicolor.