关键词: 土蜂科, 线粒体基因组, 基因重排, 核苷酸多样性, 纯化选择, 系统发育关系

Abstract: 【Aim】This study aims to understand the monophyletic and phylogenetic positions of the Scoliidae by phylogenetic analysis of the mitochondrial genome of Aculeata insects.【Methods】The mitochondrial genomes of five species of three genera of Scoliidae were sequenced by using Illumina Hiseq2500 next-generation sequencing technology, annotated and analyzed. Maximum likelihood (ML) and Bayesian inference (BI) methods were used to construct the phylogenetic tree of Aculeata insects based on the sequences of 13 protein-coding genes (PCGs) and two rRNA genes of 36 mitochondrial genomes. 【Results】The five newly sequenced mitochondrial genomes of the Scoliidae, including the mitochondrial genomes of Colpa quinquecincta (GenBank accession number: OM103696), Colpa tartara (GenBank accession number: OM103697), Megacampsomeris grossa (GenBank accession number: OM103796), Megacampsomeris formosensis (GenBank accession number: OM142776) and Scolia schrenkii (GenBank accession number: OM103797), are 15 367-20 649 bp in length, containing 37-39 genes including 13 PCGs, 2 rRNA genes (rrnL and rrnS) and 22-24 tRNA genes, with the AT content of over 75%. The start codons of all the 13 PCGs are ATN, and the stop codons are TAA or T--. In contrast to the deduced ancestral sequence, complex gene rearrangement events have occurred in the five newly sequenced mitochondrial genomes of the Scoliidae, which are mainly the changes of some gene positions in the gene region trnS1-trnE-trnF-nad5-trnH, a remote inversion phenomenon of the gene region trnI-trnQ-trnM-nad2-trnW-trnC-trnY-cox1-trnL2-cox2-trnK and the position changes of the genes trnF, trnS1, trnE, trnH and nad5. Both Ka/Ks and nucleotide diversity π of 13 PCGs indicated that cox1 is the most conserved gene. The results of the ML tree and BI tree both showed that the Scoliidae is a monophyletic group, and the Scoliidae and the Pompilidae are sister groups to each other. In the Scoliidae, Colpa and Scolia, and Megacampsomeris and Camposmeris all show close relationship.【Conclusion】This study preliminarily clarified the characteristics of the mitochondrial genomes of the family Scoliidae, laying the foundation for further research. The phylogenetic analysis based on the mitochondrial genome shows that the family Scoliidae is a single lineage.

Key words: Scoliidae, mitochondrial genome, gene rearrangement, nucleotide diversity, purification selection, phylogenetic relationship