The Complete Sequence Determination And Analysis Of Bombyx Mori Mitochondrial Genome

Prof. Zhou Zeyang Prof. Lu Cheng(The Key Sericultural Laboratory of Agricultural Ministry, Southwest.Agrictjltural University, Chongqing ,400716, China)SummaryAs a unique cytoplasmic genetic system, mitochondrial DNA(mtDNA) is a smaU, self-replicating and diverse genome. The study on mitochondnal genome is significant in the research of many biologic issues, such as gene structure and function, gene expression regulation on time and space, nucleo-cytoplasmic interaction, the dynamics of molecular evolution, the origin of mitochondna, the origin and evolution of species, and so on.Bombyx mail is an important economic Lepidopteran spinning insect and a model organism in the research of traditional genetics and molecular biology. The sequence determination of Bombyx marl mitochondnal genome will enrich the mitochondrial genome data. And through the comparative genomic analysis, the characters of gene organization and structure of Bombyx mon mitochondrlal genome will be discovered, and so will evolution characters of the genome sequence. Furthermore, the mtDNA phytogenetic relationship of different species will be illuminated.In this paper, the isolation method of Bambyx man mtDNA was discussed; the complete sequence was determinated and analyzed; and mtDNAs phylogenesis was constructed of 12 arthropod species.I Isolation method of Bombyx marl mtDNAThe mtDNA isolation method by alkaline lysis procedure was improved. mtDNA was respectively isolated from the posteria silk gland of the 5th laval stage and pupas and eggs of Bombyx man in different pH of homogenizing buffers with the ratio between the quantity of mtDNA and that of the material, and the purity of mtDNA being contrasted. Then we54 proposed a practicable isolation method． 2 Determination of Bombyx morl mtONA Using the method"Shot－gun'二mtDNA of Bomb厂x mori wasdoned randomly and sequenced．The sequence of 156llbps was attained from overlap of fragment sequences． 3GeneorganlzatlonandstructureofBombyxmorlmtDNA The complete mtDNA sequence Of BombyX mon containsl3 protein－COding genes, 22transf6r RNA(tRNA)genes,two ribosomal RNA(rRNA)genes and a498 bpsA＋T rich plon(Fig．1)．Comparison Of this sequence with the sequence of D．meI8nogsstsr mtDNAsho鹏dthattRNA恻rearranged．In mtDNAofBomb烬mon,tRNAM幻is between the A＋T rich region and tRNAll'gene while it is between tRNAGI'and NDZ genes on mtDNA of D．me伯n凹as柏厂Bomb yxyx mo门mtDNA has an A＋T COnt6nt of 81％． which is identical to that of D．mefenogster mtDNA． M rid Fig．IGene organization ofsombyx morl mltochondrlal genome 1－22·乙RNA"",tRNA""tRNA"in＊A可回"tR＊A""tRV才'"tR＼A'"'t卜NA'""tR卜A'"'t卜＊A'"' tRNA''tRNA'''tRNA'"''tRNA""'tRNA"''tRVA''"tRNA''"tRNA"" tR＼A"'IRNA""" tRNA"',tRNA'回':NDI～6 sfld ND4L:卜气COt lfldffi1L6 sd6fl二n6 dlflUC16(It二d6 dehydrogenase subun二ti～6 a口d乏L CO二～11二:C歹toe卜厂ome 0义ldase Subun［11～3: ＊T卜ase6,8:＊＊P8se C0mp］e厂fly subun门6,8:Cytb:Lytoch厂omeb:LrHNA:D。arge 1·叫A:SrRNA:加a且且rRM:A丁r计卜:A十T riCh reg二on:(iCneS()utsldC of c1CICal·e coded 二n H st＊a互n:Genes InsNe of c二1－ie are COJed In L sirs二n． The second st口Ctures of22 tRNAgenes were Prellmlnarllyconstructed．In the second struCtures OfstRNAgenes,there are mlsmatched and unmatCh6d base pal旧 55in the aareptor st6m；DHU stem,TwC咖m aM a币扣以bn的回n ll－－Peot比V Thenucleotide number Of DHU and TwC helloes v问es．旧ety bSIeen tR仰 genesex比pt anti咖on helles with typica...