棕色鳃金龟线粒体基因组全序列测定及分析

Sequencing and analysis of complete mitochondrial genome of Holotrichia titanis

  • 摘要: 【目的】测定分析棕色鳃金龟(Holotrichia titanis)线粒体基因组全序列,并基于线粒体基因组序列探讨棕色鳃金龟的系统发育关系,为揭示棕色鳃金龟的分类地位及对其进行分子生物学研究提供科学依据。【方法】利用Illumina NovaSeq二代测序技术对棕色鳃金龟的线粒体基因组进行测序,并对其基因结构特点及碱基组成进行分析。基于17种鞘翅目与3种直翅目外群昆虫的蛋白编码基因(Protein-codinggenes,PCGs)序列,应用邻接法(Neighborjoining,NJ)和最大似然法(Maximum likelihood,ML)构建系统发育进化树,分析棕色鳃金龟与其他昆虫的系统发育关系。【结果】棕色鳃金龟线粒体基因组全长16851 bp(登录号MZ726798.1),包含37个基因,分别为13个PCGs、22个t RNA基因和2个rRNA基因,以及1个非编码控制区(D-loop)。棕色鳃金龟线粒体基因组基因之间存在重叠或基因间隔区,其线粒体全基因组中AT含量占比74.30%,碱基组成表现出明显的AT偏好性(AT-skew),且AT-skew为正值,GC偏好性(GC-skew)为负值。PCGs中,cox1基因以特殊的TTG为起始密码子,其余12个基因均以典型的ATN为起始密码子。在22个tRNA基因二级结构中,除trnS1基因因缺少1个二氢尿嘧啶(DHU)导致不能形成完整的三叶草结构外,其余tRNA基因均能形成典型的三叶草结构。系统发育分析结果显示,棕色鳃金龟与暗黑鳃金龟(Holotrichia parallela)聚在同一小分支上,二者亲缘关系较近。【结论】获得了棕色鳃金龟线粒体基因组全序列,棕色鳃金龟线粒体基因组符合金龟科昆虫线粒体基因组的一般特征;棕色鳃金龟与暗黑鳃金龟在线粒体基因组学和系统发育上非常相似,在进化上有着相似的进化史。

     

    Abstract: 【Objective】To determine and analyze the complete sequence mitochondrial genome of Holotrichia titanis,and to explore the phylogenetic relationship of Holotrichia titanis based on the mitochondrial genome sequence which provided scientific basis for revealing the taxonomic status of H. titanis and studying its molecular biology. 【Method】The mitochondrial genome of H. titanis was sequenced by Illumina NovaSeq second generation sequencing technology,and the gene structure characteristics and base composition were analyzed. Based on the protein-coding genes(PCGs) sequence of 17 Coleoptera and 3 Orthopteran outgroups,neighbor-joining and maximum likelihood were used to construct a phylogenetic tree and analyze the phylogenetic relationship between H. titanis and other insects. 【Result】The mitochondrial genome of H. titanis was 16851 bp(accession number MZ726798.1),with a total of 37 genes,including 13 PCGs,22 tRNA genes and 2 rRNA genes,and 1 non-coding control region(D-loop). There were overlapping or gene spacing regions between mitochondrial genome genes,and the AT content in mitochondrial genome accounted for 74.30%,and the base composition showed obvious AT base bias(AT-skew),AT-skew had a positive value and AT-skew bias(GC-skew) had a negative value. Among the PCGs,cox 1 gene had special TTG as the start codon,and the remaining 12 genes had typical ATN as the start codon. In the secondary structures of 22 tRNA genes,except trnS1 gene could not form a complete cloverleaf structure due to the lack of a dihydroouracil(DHU),other tRNA could form a typical cloverleaf structure. The phylogenetic results showed that H. titanis clustered on the same small branch with H. parallela,and they were closely related.【Conclusion】The complete mitochondrial genome sequence of H. titanis is obtained. The mitochondrial genome of H. titanis is consistent with the general characteristics of the mitochondrial genome of Scarabaeidae. H. titanis and H. parallela are very similar in mitochondrial genomics and phylogeny,and have a similar evolutionary history.

     

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