中文摘要：

【目的】分析昆虫的线粒体基因组能很好地指示昆虫物种的亲缘关系。本研究旨在探索琥珀蚕Antheraea assama线粒体基因组并在线粒体水平上了解大蚕蛾科（Saturniidae）属及种间的分子系统进化关系。【方法】采用PCR步移法并结合克隆测序的策略,测定了珍稀绢丝昆虫琥珀蚕的线粒体基因组全序列,分析其结构特点和碱基组成;采用邻近距离法（NJ）构建大蚕蛾科及外群共14种昆虫线粒体蛋白质编码基因的系统发育树,并分析琥珀蚕在大蚕蛾科中的系统发育关系。【结果】琥珀蚕线粒体基因组序列全长15 312 bp（Gen Bank登录号：KU301792）,包含13个蛋白质编码基因、22个tRNA基因、2个核糖体rRNA基因和一段332 bp的A＋T富集区,呈现典型的鳞翅目昆虫线粒体基因组的核苷酸组成及基因排布顺序。分析结果表明,琥珀蚕线粒体基因组中A＋T含量高达80.18%,13个蛋白质编码基因中,除了COX1以CGA为起始密码子,其他均为典型的起始密码子ATN。COX1、COX2和ND5均以不完整的T为终止密码子,其余基因都是以典型的TAA或TAG为终止密码子。预测的22个tRNA二级结构中,除tRNASer（AGN）缺乏DHU臂外,其他21个tRNA均能形成典型的三叶草结构。由线粒体蛋白质基因串联序列构建的NJ系统发育树表明,琥珀蚕与柞蚕Antheraea pernyi、天蚕Antheraea yamamai、明目大蚕Antheraea frithi构成鳞翅目大蚕蛾科柞蚕属Antheraea这一分支。在9种大蚕蛾科昆虫中,琥珀蚕与柞蚕属的天蚕亲缘关系最近,与巨大蚕蛾属Attacus的乌桕大蚕Attacus atlas亲缘关系较远。【结论】琥珀蚕线粒体基因组的基因排列方式同其他已测定的鳞翅目昆虫的完全相同。基于线粒体基因组的大蚕蛾科昆虫系统发育关系与传统的形态分类学结果一致,即琥珀蚕隶属于柞蚕属Antheraea。

英文摘要：

【Aim 】 Analyzing the mitochondrial genomes of insects can well indicate the genetic relationship among insect species. This study aims to explore the mitochondrial genome of Antheraea assama and to understand the intergeneric and interspecific molecular and evolutionary relationships of Saturniidae based on the mitochondrial genome sequences. 【Methods 】 The complete mitochondrial genome sequence of Antheraea assama,a rare silk-spinning insect,was determined by using PCR and primer walking,and its general features and base composition were analyzed. The phylogenetic tree of mitochondrial protein-coding genes of fourteen species of Saturniidae and the outgroup was constructed by using the neighbor-joining method（ NJ）, and the phylogenetic relationships of A. assama within Saturniidae were analyzed. 【Results】The mitochondrial genome of A. assama（ Gen Bank accession no. ：KU301792） is 15 312 bp in length,and contains 13 protein-coding genes（ PCGs）,22 tRNA genes,2ribosomal RNA genes and a 332 bp A ＋ T-rich region. The sequenced genome displays the genomic components and gene order of the typical lepidopteran mitochondrial genome. The sequence analysis revealed that the mitochondrial genome of A. assama is biased toward a high A ＋ T content（ 80. 18%）.All protein-coding genes start with a typical ATN initiation codon,except that COX1 starts with the CGA codon. Majority of the 13 PCGs have a complete termination codon（ TAA or TAG）,except that COX1,COX2 and ND5 genes terminates with the incomplete stop codon T. The secondary structure of 22 tRNA genes by predicting showed the classic clover-leaf structure,except that the dihydrouridine（ DHU） arm of tRNASer（ AGN）forms a simple loop. The NJ tree based on the mt DNA protein-coding gene sequences showed that A. assama formed the clade of Antheraea（ Lepidoptera： Saturniidae） with Antheraea pernyi,Antheraea yamamai and Antheraea frithi. In nine species of Saturniidae studied,A. assama has the closest relationship with A. yamama