Mitochondrial genomes and phylogeny of Atratus and Educator Group species of the Melanoconion Section of Culex (Melanoconion) (Diptera: Culicidae)

Abstract

Background: Culex (Melanoconion) species are known to act as vectors for different arboviruses, and little is known about the mitochondrial genome of these species.

Objectives: Aiming to expand the genetic knowledge of this subgenus, a 12Kb fragment of the mitochondrial genome was sequenced from 23 specimens belonging to the Atratus and Educator Groups of the subgenus Melanoconion of Culex.

Methods: The sequenced specimens were morphologically identified as Culex dunni, Culex ensiformis, Culex theobaldi, Culex trigeminatus, Culex eknomios, Culex zeteki, Culex near commevynenis, Culex angularis, Culex longistriatus, and Culex near vaxus. The reads were assembled with the reference genome of Culex quinquefasciatus and MITOS2 was used for gene annotation. Values of guanine-cytosine (GC) and adenine-thymine (AT) skews, nucleotide diversity, ratio between non-synonymous (Ka) and synonymous (Ks) substitution, and nucleotide composition were calculated, and phylogenetic analysis was performed.

Findings: As in other Culex mitogenomes, the partial mitochondrial genomes include 12 protein coding genes (PCGs), 15 tRNA, and 1 rRNA (rrnL). The PCGs showed no length variation between the species studied. ND5 gene presented one less base in the new sequences, which generated a stop codon and, consequently, a shorter length in relation to the Cx. quinquefasciatus sequence reference. All specimens showed a positive value for AT-skew and negative for GC-skew. Nucleotide diversity varied between 0.00407 and 0.12085. Ka/Ks values ranged from 0.0 to 2.775.

Main conclusions: Leucine and Serine were the most abundant amino acids. Phylogenetic analysis suggested three putative species.