大卫绢蛱蝶线粒体基因组全序列测定和分析

Sequencing and analysis of the complete mitochondrial genome of Calinaga davidis Oberthür(Lepidoptera:Nymphalidae)

目前有关蝶类线粒体基因组全序列及其分子进化的研究报道还不多见。本文利用long PCR和引物步移法得到大卫绢蛱蝶Calinaga davidis的线粒体基因组全序列,同时就其基因组成和结构特点作了初步分析。结果显示：其基因组全长为15 267 bp（GenBank登录号为HQ658143）,包括13个蛋白质编码基因（ATP6,ATP8,COI-III,ND1-6,ND4L,Cytb）、22个tRNA基因、2个rRNA基因（16S和12S）以及非编码的控制区。与其他鳞翅目昆虫相一致,其基因组未出现基因重排现象。基因组共包含11个基因间隔区,总长度为130 bp,间隔长度1~46 bp,最大间隔在tRNAGln与ND2基因之间;基因间共存在13处重叠,总长度为66 bp,重叠碱基数1~35 bp,最长的重叠区位于COII与tRNALys基因。lrRNA和srRNA基因长度分别为1 337 bp和773 bp;除tRNASer（AGN）缺少二氢尿嘧啶臂（DHUstem）,在相应的位置上只形成一个简单环外,其余的tRNA基因都能形成典型的三叶草结构。13个蛋白编码基因总长度为11 247 bp,共有3 737个密码子,它们的碱基组成和密码子的使用具有明显的偏倚性;除COI外（起始密码子TTG）,其余的12个蛋白质编码基因都以标准的ATN作为起始密码子;COI基因终止密码子为不完全T,ND4基因终止密码子为不完全TA,其余基因都以TAA为终止密码子。A＋T丰富区全长为389 bp,A＋T含量高达92.0%,其中存在2段类似微卫星的重复序列（TA）6和（AAT）4。本文的研究结果为探讨绢蛱蝶亚科在蛱蝶科中的系统学地位及其与其他亚科间的系统发生关系等问题提供了重要的分子生物学数据。

Up to now,the reports about the complete mitochondrial genome of butterflies and their corresponding molecular evolutions are still limited.In this paper,the complete mitochondrial genome（mitogenome） of Calinaga davidis was sequenced and analyzed using the long PCR and the conserved primer walking technology.The results showed that the entire mitochondrial genome sequence was 15 267 bp long（GenBank accession no.HQ658143）,containing 13 protein-coding genes（ATP6,ATP8,COI-III,ND1-6,ND4L and Cytb）,22 transfer RNA genes,2 ribosomal RNA genes（lrRNA and srRNA） and a putative control region（D-loop）.All the 37 genes are arranged in the same orientations as those of other lepidopteran species determined;and there are 11 intergenic spacer sequences totalling 130 bp（1 bp to 46 bp for each sequence） and 13 overlapping sequences totalling 66 bp（1 bp to 35 bp for each sequence）,interspersed throughout the genome,and the largest（46 bp） spacer region and overlapping region are located between the tRNAGln and ND2,and between COII and tRNALys genes,respectively.The large and small rRNA genes are 1 337 bp and 773 bp in size,respectively.All the tRNA genes have typical leaf clover secondary structures,except for the tRNASer（AGN）,whose DHU arm forms a simple loop.The 13 protein-coding genes are 11 247 bp in length with corresponding 3 737 codons,their base compositions have a relatively higher AT bias and their codon usages are also predominantly A＋T-rich.All the protein coding genes（PCGs） use standard initiation codons ATN,except for the COI gene,which uses TTG as its starting codon,and all the PCGs use common stop codon（TAA）,except for the COI and ND4 genes,which terminate into a single T and TA,respectively.The A＋T-rich region is 389 bp in length with the AT content up to 92.0%,and this region contains two microsatellite-like repeating sequences（TA）6 and（AAT）4.The results of this study provide some important molecular data to clarify the systematical status of Calinaginae,as well as its phylogenetic relationship with other nymphalid subfamilies.