Mitochondrial genomes and comparative analyses of Culex camposi, Culex coronator, Culex usquatus and Culex usquatissimus (Diptera:Culicidae), members of the coronator group.
BACKGROUND
The Coronator Group currently encompasses six morphologically similar species (Culex camposi Dyar, Culex coronator Dyar and Knab, Culex covagarciai Forattini, Culex usquatus Dyar, Culex usquatissimus Dyar, and Culex ousqua Dyar). Culex coronator has been incriminated as a potential vector of West Nile Virus (WNV), Saint Louis Encephalitis Virus (SLEV), and Venezuelan Equine Encephalitis Virus (VEEV). The complete mitochondrial genome of Cx. coronator, Cx. usquatus, Cx.usquatissimus, and Cx. camposi was sequenced, annotated, and analyzed to provide genetic information about these species.


RESULTS
The mitochondrial genomes of Cx. coronator, Cx. usquatus, Cx.usquatissimus, and Cx. camposi varied from 15,573 base pairs in Cx. usquatus to 15,576 in Cx. coronator. They contained 37 genes (13 protein-encoding genes, 2 rRNA genes, and 22 tRNA genes) and the AT-rich control region. Comparative analyses of the 37 genes demonstrated the mitochondrial genomes to be composed of variable and conserved genes. Despite the small size, the ATP8, ATP6 plus NADH5 protein-encoding genes were polymorphic, whereas tRNAs and rRNAs were conserved. The control region contained some poly-T stretch. The Bayesian phylogenetic tree corroborated that both the Coronator Group and the Culex pipens complex are monophyletic taxa.


CONCLUSIONS
The mitochondrial genomes of Cx. coronator, Cx. usquatus, Cx. usquatissimus and Cx. camposi share the same gene composition and arrangement features that match to those reported for most Culicidae species. They are composed of the same 37 genes and the AT-rich control region, which contains poly-T stretches that may be involved in the functional role of the mitochondrial genome. Taken together, results of the dN/dS ratios, the sliding window analyses and the Bayesian phylogenetic analyses suggest that ATP6, ATP8 and NADH5 are promising genes to be employed in phylogenetic studies involving species of the Coronator Group, and probably other species groups of the subgenus Culex. Bayesian topology corroborated the morphological hypothesis of the Coronator Group as monophyletic lineage within the subgenus Culex.
Departamento de Epidemiologia, Faculdade de Saúde Pública, Universidade de São Paulo, São Paulo, Brazil. bruna-demary@usp.br.
Bruna
B
Demari-Silva
Department of Life Sciences, Natural History Museum, Cromwell Road, London, England. p.foster@nhm.ac.uk.
Peter G
PG
Foster
Departamento de Epidemiologia, Faculdade de Saúde Pública, Universidade de São Paulo, São Paulo, Brazil. porangaba@usp.br.
Tatiane M P
TM
de Oliveira
Superintendência de Controle de Endemias, Secretaria de Estado da Saúde de São Paulo, Araraquara, São Paulo, Brazil. edusteber@uol.com.br.
Eduardo S
ES
Bergo
Department of Pathology, LIM 03, Hospital das Clínicas (HC), School of Medicine, University of São Paulo, São Paulo, Brazil. sabyem_63@yahoo.com.
Sabri S
SS
Sanabani
Department of Pathology, LIM 03, Hospital das Clínicas (HC), School of Medicine, University of São Paulo, São Paulo, Brazil. rodrigo_pessoa1@hotmail.com.
Rodrigo
R
Pessôa
Departamento de Epidemiologia, Faculdade de Saúde Pública, Universidade de São Paulo, São Paulo, Brazil. masallum@usp.br.
Maria Anice M
MA
Sallum
D000818:Animals; D001482:Base Composition; D001938:Brazil; D003062:Codon; D019295:Computational Biology; D003465:Culex / Q000145:classification / Q000235:genetics*; D017344:Genes, Insect; D050259:Genes, Mitochondrial; D049750:Genome, Insect; D054629:Genome, Mitochondrial; D023281:Genomics / Q000379:methods; D059014:High-Throughput Nucleotide Sequencing; D007303:Insect Vectors; D058977:Molecular Sequence Annotation; D016366:Open Reading Frames; D010802:Phylogeny
D003062:Codon