ABSTRACT

In Colombia, the mosquito Ochlerotatus taeniorhyn­chus has been identified as an efficient vector of the epidemic-epi­zootic Venezuelan equine encephalitis virus. We evaluated the ge­netic variability and heterogeneity of this mosquito in Colombian populations using eight microsatellite DNA loci. Two hundred and ten mosquito specimens collected from seven populations of the Co­lombian Atlantic coast (San Bernardo del Viento, Coveñas, Carta­gena, Barranquilla, Ciénaga, Dibulla, and Riohacha) were analyzed. We found five polymorphic microsatellite loci, with 19 alleles giv­ing 62.5% polymorphism; the mean number of alleles per locus was 3.8. The mean expected heterogeneity ranged from 0.568 to 0.660. Most of the polymorphic microsatellite loci were in Hardy-Wein­berg disequilibrium, due to both deficit and excess of heterozygotes. The Fst statistic gave a total value of 0.0369, reflecting low ge­netic differentiation among the populations and, as a consequence, a low degree of structuring among them, while gene flow was high (Nm = 6.52); these findings point to genetic homogeneity among these populations. There was no significant linkage disequilibrium between genotype pairs of the various populations. We concluded that this mosquito is distributed in local populations along the Co­lombian Atlantic coast; these findings will be useful for developing strategies for controlling this vector.

Key words: Genetic variability, Ochlerotatus taeniorhynchus, Genetic heterogeneity, Venezuelan equine encephalitis virus, Polymorphic microsatellite loci.