Novel DNA extraction assay for molecular identification of Aedes spp eggs

Aedes aegypti and A. albopictus represent the two most important species of mosquitoes in relation to dengue virus transmission both in the Americas and Asia. However, the study of theses species generally requires the establishment of a colony for the larvae to hatch, or waiting for the adult development to perform its taxonomic classification, which is time consuming. Thus, the establishment of new methods aimed at obtaining DNA directly from the mosquito eggs is relevant. Accordingly, we compared a new approach based on Chelex(®) 100 resin with the standard STE method to extract DNA from the eggs of Aedes spp to molecularly identify these vectors. The Chelex(®) 100 resin approach was very efficient, as satisfactory amounts of DNA were obtained, making it possible to amplify and sequence a mitochondrial DNA barcode region widely used to identify species. The STE protocol yielded substantial amounts of DNA, but the 260/280 optical density ratio indicated a low quality, precluding amplification. This new method proved quite effective in obtaining DNA from even a single mosquito egg, and it can thus be applied in population genetic studies of various vector insects to enhance monitoring programs.