Sequencing Of The Six Mitochondrial Genomes Of Eupelmids And Phylogenetic Analysis In Chalcidoidea

As an important parasitic natural enemy insect,eupelmides wasp exist widely in tropical and subtropical areas.However,due to the late start of the taxonomic study of this group,the small size of individuals and little morphological differences between some species,it is always difficult to classify them based on morphology.With the progress of technology,molecular data are increasingly used in classification and phylogenetic studies,especially mitochondrial genome data obtained by next-generation sequencing which is becoming more and more widely used in phylogenetic and population genetic studies.In this study,we sequenced the mitochondrial genomes of six different species in three genera of the family Eupelmidae,namely Anastatus dexingensis,Anastatus shichengensis,Anastatus fulloi,Merostenus sp.1,Merostenus sp.2,and Eupelmus anpingensis.The following conclusions can be drawn from the analysis of these six different species with relevant bioinformatics software:1.All mitochondrial genes of Anastatus dexingensis,Anastatus shichengensis and Merostenus sp.1 were obtained,the full length of these genomes were 16,162 bp,15,163 bp and 16,370 bp,the A+T content were83.2%,83.5% and 82.7% respectively;partial of control region in Eupelmus anpingensis was not obtained,and the length of mitochondrial genome was 15,479 bp,A+T content was 83.3%;The genes of trn M,trn Q,trn T,trn V and rrn S were not obtained in Merostenus sp.2,and the length is 14,773 bp,A+T content was 81.8%;The genes of trn M and trn V in Anastatus fulloi were not obtained,and the length was 14,738 bp,A+T content was 82.7%.2.According to the prediction of the secondary structures of t RNA genes of these six species on the mitos2 web server,the secondary structure of most t RNA genes is typical cloverleaf structure,and there are also other structures,such as the absence of DHU arm in trn S1 of all species and the absence of anti-codon ring and DHU arm in trn E of species Eupelmus anpingensis.Further investigation revealed that the G-U mismatch was the most common of all the mismatched base pairs.3.13 protein-coding genes from six species,except for Merostenus sp.2,whose cox2 gene start codon is TTG,all protein-coding genes from other species are ATN,and most protein-coding genes were terminated with TAA,meanwhile a few genes were used TAG as a stop codon.By calculating the Relative Synonymous Codons Using(RSCU),it was found that UUA,UUU,AUA,and AUU were used the most frequently used among all codons,which is consistent with the obvious AT bias of mitochondrial genomes of insects.4.The mitochondrial gene orders of the six species were compared with the ancestral gene order(Drosophila yakuba),and it was found that serious gene rearrangements occurred in the mitochondrial genes of these six species,mainly occurred in t RNA genes,but it also includes protein-coding genes and r RNA genes,the rearrangement types including transposition,shuffle,and inversion.5.Based on 13 protein-coding genes,and combined with mitochondrial genomes of other Chalcidoidea published in Gen Bankthe,both maximum likelihood tree(ML)and Bayesian tree(BI)showed Mymaridae+(Chalcididae+ other Chalcidoidea),but at the same time,there was no consistent result for other groups.