Complete sequence determination and analysis of mitochondrial genome of Epiverta chelonia (Mader, 1933) (Coleoptera: Coccinellidae)

Abstract

[Objective] The purpose of the study was to clarify the structural characteristics of the mitochondrial genome of Epiverta chelonia (Mader, 1933) and analyze its phylogenetic relationship, so as to provide data support for the study of the origin, differentiation and genetic diversity of E. chelonia.

[Method] The mitochondrial genome of E. chelonia was sequenced by using Illumina next-generation sequencing technology, and the genome sequence was annotated and analyzed. Maximum likelihood and Bayesian methods were used to construct the phylogenetic evolutionary tree based on the 13 protein-coding genes (PCGs) of mitochondrial genomes of 11 species of insects from 3 subfamilies of Coccinellidae (Epilachninae, Coccinellinae and Scymninae).

[Result] The mitochondrial genome of E. chelonia was 17347 bp in length, including 37 genes (13 PCGs, 22 tRNA genes, 2 rRNA genes) and one non-coding region, 11 gene overlapping regions and 9 gene spacer regions. The genome had the typical gene organization and sequence of mitochondrial genome from Coleoptera insects, with the AT content of 75.77%, showing obvious AT skew. Among the 13 PCGs, all genes used ATN as the start codon, except for cox1 gene, which used TTG as the start codon. Eleven genes used TAA as the termination codon, only nad1 and nad3 genes used TAG as the termination codon. Except for trnS1 gene, the secondary structures of the remaining 21 tRNAs were the typical clover-leaf structure, with a small number of mismatches of G-U base in the secondary structure. Phylogenetic analysis showed that E. chelonia and Subcoccinella vigintiquatuorpunctata were on the same branch.

[Conclusion] The mitochondrial genome of E. chelonia conforms to the general characteristics of Coccinellidae mitochondrial genome. E. chelonia is closely related to S. vigintiquatuorpunctata, which is in accordance with the traditional morphological classification.

Abstract

摘要：【目的】 明确龟瓢虫[ Epiverta chelonia (Mader, 1933)]线粒体基因组结构特征, 分析其系统发育关系, 为龟 瓢虫的起源、分化和遗传多样性研究提供数据支持。 【方法】利用Illumina二代测序技术测定龟瓢虫线粒体基因组, 对 基因组序列进行注释和分析; 基于瓢虫科 (Coccinellidae) 3亚科［食植瓢虫亚科 (Epilachninae) 、瓢虫亚科 (Coccinellinae) 和小毛瓢虫亚科 (Scymninae) ］11种昆虫的线粒体基因组13个蛋白编码基因 (Protein-coding genes, PCGs), 采用 最大似然法和贝叶斯法构建系统发育进化树。 【结果】龟瓢虫线粒体基因组全长17347 bp, 包含37个基因 (13个PCGs、 22个tRNA基因和2个rRNA基因) 和1个非编码的控制区, 基因重叠区域共11处, 间隔区域共9处。基因组拥有鞘翅目 昆虫典型线粒体基因组的基因组成和排列顺序, AT含量为75.77%, 表现明显的AT偏向性。13个PCGs中除 cox1基因 以TTG为起始密码子外, 其余均以ATN为起始密码子; nad1和 nad3基因以TAG为终止密码子, 其余11个基因以TAA为 终止密码子。除 trnS1基因外, 其余21个tRNA的二级结构均为典型的三叶草结构, 二级结构中出现少量的G-U碱基错 配现象。系统发育进化分析结果表明, 龟瓢虫与苜蓿瓢虫 ( Subcoccinella vigintiquatuorpunctata) 处于同一分支上。 【结论】龟瓢虫线粒体基因组符合瓢虫科昆虫线粒体基因组的一般特征; 龟瓢虫与苜蓿瓢虫的亲缘关系较近, 与传统 的形态学分类相一致。