Comparative Mitochondrial Genomics And Phylogeny Of Dolichovespula

The members of the genus Dolichovespula(Hymenoptera: Vespidae: Vespinae)are known to show highly developed eusocial behaviour.In China eleven species have been found,out of the twenty species of Dolichovespula known world-wide.The classification of Dolichovespula and the study of the phylogenetic relationships is hampered by the similarity of morphological features and the limited results of molecular research.The genus Dolichovespula was divided into six species groups with their distributions by Archer.Thanks to molecular biology,the mitochondrial genomes are widely used in phylogenetic studies;mitochondrial genomes have the advantages of maternal inheritance,stable gene content and predictable arrangement.Next-generation sequencing technology makes it easy to obtain complete sequences of mitochondrial genomes.In this study,thirteen proteincoding genes were used for the construction of phylogenetic trees.The main results are:(1)Five mitochondrial genomes of Dolichovespula species were sequenced by nextgeneration sequencing for the first time.Each mitochondrial genome contained 37 genes and a partly A+T-rich region.The mitochondrial genome size,gene content,gene region,gene arrangement,A+T content,codon usage as well as the tRNA secondary structures were analyzed.(2)General features of the Dolichovespula mitochondrial genomes were analyzed using the comparative mitogenomic approach.Every mitochondrial genome had an A+T content of higher than 80% and a different size of the A+T-rich region.There were 23 and 14 genes located in the major and minor coding strands,respectively.The gene with the highest A+T content was atp8 and the lowest one was cox1.Frequent gene rearrangements occurred in the same region and most rearrangements were about tRNAs.Local inversion of trnS1 only occurred in Dolichovespula lama,other rearrangement events such as translocation,gene shuffling and remote inversion occurred in all five mitochondrial genomes.(3)The phylogeny of the included Vespidae was reconstructed based on nucleotide sequences and amino acid sequencing of 13 protein-coding genes.The phylogenetic analysis showed a sister group relationship between Dolichovespula panda and Dolichovespula lama as well as Dolichovespula saxonica and Dolichovespula xanthicincta.Dolichovespula flora came out as the sister of both groups.Vespa showed up as more closely related to Vespula than to Dolichovespula in most results.The results corroborated the known relationship of Eumeninae as sister of the Polistinae + Vespinae within the Vespidae.