Genetic variability and heterogeneity of Venezuelan equine encephalitis virus vector Ochlerotatus taeniorhynchus (Diptera: Culicidae) populations of the Colombian Atlantic coast, based on microsatellite loci

Abstract

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.

Population Genetic Structure of Aedes fluviatilis (Diptera: Culicidae)

“…This phenomenon has previously been observed in Ae . taeniorhynchus mosquito populations from Colombia [52,53]. …”

Analysis of the genetic variability and structure of Ochlerotatus taeniorhynchus (Diptera: Culicidae) populations from the Colombian Atlantic coast on the basis of random amplified polymorphic DNA markers

“…Bello and Ruiz-García (2009) estimated a genetic heterogeneity of F ST = 0.069 among the same mosquito populations by means of isoenzymes, as well as a gene flow estimate of N m = 3.39. Bello and Becerra (2009) estimated values of F ST = 0.0369 and N m = 4.97 using microsatellites in these same populations (all of the gene flow estimates were corrected for an n-dimensional island model). Thus, all of these genetic heterogeneity coefficients, as well as the gene flow estimates, were very similar independently of each one of the 3 types of markers employed, which represented completely neutral markers (RAPDs), neutral markers with some regulatory functions (microsatellites), and structural markers (isoenzymes).…”

“…In the first study, an isoenzyme analysis (Bello and Ruiz-García, 2009) was undertaken; meanwhile, in the second study, microsatellite loci were employed (Bello and Becerra, 2009). The results of these studies demonstrated, in general, low genetic differentiation among the populations that were analyzed, with relatively high levels of genetic variability and high values of gene flow.…”

Genetic analysis of scattered populations of the Indian eri silkworm, Samia cynthia ricini Donovan: differentiation of subpopulations

“…Continuous mountain ranges, by restricting gene flow between scattered populations, have contributed significantly to the large-scale inbreeding, excess of homozygotes and stabilization of divergent sub-populations, which have ultimately led to the Wahlund effect (Wahlund, 1928), as noticed earlier in Anopheles arabiensis (Kamau et al , 2007), the Atlantic dipteran, Ochlerotatus taeniorhynchus (Bello and Becerra, 2009), and wild populations of the muga silkworm, Antheraea assama (Arunkumar et al , 2009). The availability of local congenial survival conditions was evident by most of the eri populations having been uniformly distributed on the ALSCAL matrix.…”