Study On The Mitochondrial Genome And Molecular Phylogeny Of Drosophila

The family Drosophilidae represents a widespread and species-rich taxon within the order Diptera.Due to their remarkable variation in morphology,ecology and other life history traits,many species of this family have been widely used in various research fields of life sciences.To better understand the biological patterns and processes,it has become increasingly popular to employ a comparative biology approach.Thus,a good knowledge of its phylogeny would provide a useful background framework for such studies.Besides,species of this family have a wide spectrum of vectors,and many of them could cause serious economic losses.And a rapid species identification would be essential to their control and management,but needs powerful tools.In this research,a batch of mitochondrial genomes of the family Drosophilidae were obtained by data-mining and reusing the previously published high-throughput data from NCBI-SRA database.Furthermore,I reconstructed the phylogeny of the family,and investigated the taxonomic framework at varying taxonomic levels(i.e.subfamily,genus,subgenus,species group,species subgroup).Base on this,the evolution of the mitogenomic structure was further discussed.The key findings of this study are summarized as follows:(1)Fifty-two mitochondrial genomes from 50 species were successfully retrieved by data mining,including 34 complete and 18 nearly complete mitochondrial genomes.(2)As in most other animals,the mitochondrial genomes harbor the typical set of 37 mitochondrial genes(incl.13 protein-coding genes,22 tRNA and 2 rRNA genes)and an A+T-rich non-coding control region.The gene arrangement is conservative,but the mitogenomic sizes vary greatly among species,which could be directly related to the size variation in the control region and noncoding intergenic spacers.(3)Phylogenetic analysis based on the Bayesian and maximum-likelihood analysis of the concantenated sequences of the 13 protein-coding genes well supports the current taxonomic framework at the levels of subfamily and species group,but challenges those at the levels of genus,subgenus and species subgroup.Especially,the taxonomy of the genus Drosophila and its relationship to other consubfamilial genera still remains to be investigated.