The Open Tropical Medicine Journal, 2011, 4, 11-20 11 1874-3153/11 2011 Bentham Open Open Access Genetic Diversity in Dengue Mosquito, Aedes aegypti (Diptera: Culicidae) from Amazon Region: Comparative Analysis with Isozymes and RAPD Loci Joselita Maria Mendes dos Santos *,1,2 , Elmary C. Fraga 3 , Juracy F. Maia 1 and Wanderli P. Tadei 1,2 1 Instituto Nacional de Pesquisas da Amazônia, Coordenação de Pesquisas em Ciências da Saúde, Laboratório de Malária e Dengue, Manaus, AM, Brazil 2 Universidade do Estado do Amazonas, Manaus, AM, Brazil 3 Universidade Estadual do Maranhão, Departamento de Biologia, Caxias, Maranhão, Brazil Abstract: Four populations of Aedes aegypti from Manaus were studied, using allozymes and RAPD loci, to determine intra- and interpopulation genetic variability and differentiation and to compare genetic structure parameters assessed with both markers. Five RAPD primers produced 52 polymorphic fragments, whereas only seven of 18 isozyme loci were polymorphic. The population from Praça 14 was the most polymorphic (P= 94.23% and P= 55.6%); while those from Coroado (P= 82.69% and P= 44.40%) and from Cidade Nova (P= 84.61% and P= 44.40%) were the least polymorphic, for both RAPD and isozymes respectively. The observed heterozygosity was higher between populations (Ho= 0.33 – 0.38) as assessed by RAPD. Wright’s F statistics showed an F is value higher than F st (F is = 0.164 > F st = 0.048). AMOVA indicated that 95.12% of the genetic variability is intrapopulational. Even so, both of the genetic markers evaluated showed a relatively high gene flow ((N m = 15.15), and possibly are still random couplings, although the F is value was not low. The genetic distance between populations was similarly low for both markers: RAPD (0.012 – 0.016) and Isozymes (0.003 – 0.016). These results show that as assessed by both markers, the populations are genetically similar, and that isozymes (codominant) are the most efficient to detect the population genetic structure. Although isozymes revealed less genetic diversity than RAPDs, the estimated levels of genetic distance were identical. Keywords: Population genetics, isozymes, RAPD, dengue vector, Amazonas. INTRODUCTION Aedes (Stegomyia) aegypti Linnaeus is the main vector of yellow-fever virus and of four serotypes of dengue virus and dengue hemorrhagic fever. This mosquito originated in the Old World, probably from the Ethiopian region, and was originally described in Egypt [1]. The species currently has an almost cosmotropical distribution. Aedes aegypti was reintroduced into Brazil in 1967 and has now infested the entire country [2]. In recent years, dengue cases in Brazil have increased, and dengue fever has become one of the major public-health problems; the number of cases reported in 2007 (559,954) represents an increase of more than 100% since 2005 (248,189 cases) [3]. In Amazonas, Ae. aegypti was detected in 1996 in the city of Manaus, and today high population rates of this mosquito have been recorded, indicating the magnitude of the problem in the region [4, 5]. Unfortunately, the situation has worsened in recent years, especially due to the increasing number of cases of dengue hemorrhagic fever. The epidemiological importance and the ease of labora- tory manipulation of Ae. aegypti have facilitated studies on *Address correspondence to this author at the Instituto Nacional de Pesquisas da Amazônia, Laboratório de Malária e Dengue, P.O. Box 478, Manaus, Amazonas, Brazil; Tel: +559236433062; Fax: +559236433061; E-mail: jsantos@inpa.gov.br its population genetics and molecular biology [5-13]. Many markers have been used in studies on genetic variability and differentiation, in an attempt to quantify and explain this variability, in terms of its origin, maintenance, and impor- tance to evolution. In addition, different factors may con- tribute to the gene action that leads to the development of differentiated characteristics with respect to vector com- petence, resistance to insecticides, and ecological adaptation. Knowledge of the genetic structure of these populations may contribute to the development of control programs for this vector. The isozyme loci segregate as codominant alleles and can therefore be used for the Hardy-Weinberg equilibrium test. So, through the analysis of the estimated intra- and inter- population genetic variability and differentiation, valuable information is obtained to determine strategies for mosquito control. RAPD-PCR (Random Amplified Polymorphic DNA – Polymerase Chain Reaction) markers, which use only an arbitrary primer and amplify unknown regions of the DNA molecule, are also useful to determine genetic variability and to identify cryptic species in Culicidae. Nonetheless, they are not applicable to the Hardy-Weinberg equilibrium test [14]. In the present investigation, four populations of Ae. aegypti from Manaus were studied with the aim of estimat- ing the genetic variability and differentiation, by comparing the genetic structure parameters between RAPD (dominant) and Isozyme (codominant) loci.