Evolution of mitochondrial and ribosomal gene sequences in anophelinae (Diptera: Culicidae): implications for phylogeny reconstruction

Abstract

In this study, two mitochondrial genes, cyt b and ND5, and the D2 expansion segment of the 28S nuclear ribosomal gene were used to reconstruct a phylogeny of the mosquito subfamily Anophelinae. The ingroup consisted of all three genera of Anophelinae and five of six subgenera of Anopheles. Six genera of Culicinae were used as the outgroup. Extreme conservation at the protein level coupled with rapid saturation of synonymous positions probably accounted for the lack of meaningful phylogenetic signal in the cyt b gene. In contrast, abundant variation at all codon positions of the ND5 gene allowed recovery of the basal and most of the recent relationships. Phylogenetic analysis of D2 produced results consistent with those of ND5. Combined analysis indicated well-supported monophyletic Anophelinae (with Chagasia basal), Anopheles + Bironella, and subgeneric clades within the genus Anopheles. Moreover, subgenera Nyssorhynchus and Kerteszia were supported as a monophyletic lineage. The Kishino-Hasegawa test could not reject the monophyly of Anopheles, whereas the recently proposed hypothesis of close affinity of Bironella to the subgenus Anopheles was rejected by the analyses of ND5 and combined data sets. The lack of resolution of Bironella and Anopheles clades, or basal relationships among subgeneric clades within Anopheles, suggests their rapid diversification. Recovery of relationships consistent with morphology and previous molecular studies provides evidence of substantial phylogenetic signal in D2 and ND5 genes at levels of divergence from closely related species to subfamily in mosquitoes.