Genetic variability among Anopheles species belonging to the Nyssorhynchus and Anopheles subgenera in the Amazon region

Raquel Borges Moroni,Wanderli Pedro Tadei,Joselita Maria Mendes Dos Santos,Juracy De Freitas Maia

doi:10.1590/s0037-86822010000400015

Abstract

Isoenzymatic analyses were performed involving species of the Nyssorhynchus and Anopheles subgenera in order to estimate the intra and interspecies genetic variability. Mosquitoes were caught at different localities in the Amazon region. The collection and rearing of mosquitoes in the laboratory followed specific protocols. For the genetic variability analyses, the technique of horizontal electrophoresis on starch and starch-agarose gel with appropriate buffer systems was used. The alloenzyme variation was estimated using the Biosys-1 software. Out of the 13 loci, eight were polymorphic. Anopheles nuneztovari presented the largest number of alleles per locus, while the smallest number was detected in Anopheles marajoara from Macapá. The largest number of polymorphic loci was found for Anopheles marajoara from Maruanum and the smallest for Anopheles benarrochi (Guayará Mirim). Anopheles darlingi (Macapá) presented the greatest heterozygosity (Ho = 0.167 +/- 0.071), while the lowest heterozygosity (Ho = 0.045 +/- 0.019) was observed in Anopheles intermedius (Pacoval) of the subgenus Anopheles. Wright's F coefficient revealed considerable genetic structuring between the populations of Anopheles darlingi (Fst = 0.110) and between the populations of Anopheles marajoara (Fst = 0.082). Considering all the species studied, the genetic distance ranged from 0.008 to 1.114. The greatest distance was between Anopheles mattogrossensis and Anopheles oswaldoi, while the smallest was between the Anopheles benarrochi populations.

Highlights

Isoenzymatic analyses were performed involving species of the Nyssorhynchus and Anopheles subgenera in order to estimate the intra and interspecies genetic variability
Li and Wilkerson[7] cloned and sequenced the ITS2 region of ribosomal DNA (rDNA) extracted from the four species belonging to the Albitarsis complex and, despite obtaining significant divergence in one clone from two individuals of Anopheles marajoara from Venezuela, they were unable to distinguish Anopheles albitarsis E from Anopheles marajoara
MDH1 was polymorphic for the majority of the species, except for Anopheles triannulatus, Anopheles marajoara from Macapá, Anopheles darlingi from Timbozinho and Anopheles intermedius

Summary

Introduction

Isoenzymatic analyses were performed involving species of the Nyssorhynchus and Anopheles subgenera in order to estimate the intra and interspecies genetic variability. Species of the subgenus Anopheles found in Brazil have not been identified as malaria vectors[11], which is probably the reason for so few studies regarding the genetic structure of populations of these species[20]. MDH1 was polymorphic for the majority of the species, except for Anopheles triannulatus, Anopheles marajoara from Macapá, Anopheles darlingi from Timbozinho and Anopheles intermedius.

Results

Conclusion