Population structure and genetic divergence in Anopheles nuneztovari (Diptera : Culicidae) from Brazil and Colombia

Anopheles nuneztovari is considered an important vector of human malaria in several localities in Venezuela and Colombia. Its status as a vector of hu man malaria is still unresolved in areas of the Brazilian Amazon, in spite of have been found infected with Plasmodium sp.. For a better understanding of the genetic differentiation of populations of A. nuneztovari, electroph oretic analysis using 11 enzymes was performed on four populations from Bra zil and two from Colombia. The results showed a strong differentiation for two loci: alpha-glycerophosphate dehydrogenase (alpha-Gpd) and malate dehyd rogenase (Mdh) from 16 loci analyzed. Diagnostic loci were not detected. Th e populations of A. nuneztovari from the Brazilian Amazon showed little gen etic structure and low geographic differentiation, based on the F-IS (0.029 ), F-ST (0.070), and genetic distance (0.001-0.032) values. The results of the isozyme analysis do not coincide with the indication of two Lineages in the Amazon Basin by analysis of mitochondrial DNA, suggesting that this ev olutionary event is recent. The mean F-ST value (0.324) suggests that there is considerable genetic divergence among populations from the Brazilian Am azon and Colombia. The genetic distance among populations from the Brazilia n Amazon and Colombia is ranges from 0.047 to 0.148, with the highest value s between the Brazilian Amazon and Sitronela (SIT) (0.125-0.148). These res ults are consistent with those observed among members of anopheline species complexes. It is suggested that geographic isolation has reduced the gene flow, resulting in the genetic divergence of the SIT population. Dendrogram analysis showed three large groups: one Amazonian and two Colombia, indica ting some genetic structuring. The present study is important because it at tempted to clarify the taxonomic status of A. nuneztovari and provide a bet ter understanding of the role of this mosquito in transmission of human mal aria in northern South America.