genetic variability of a population of aedes aegypti from paraná, brazil, using the mitochondrial nd4 gene. to analyze the genetic variability of populations of aedes aegypti, 156 samples were collected from 10 municipalities in the state of paraná, brazil. a 311 base pairs (bp) region of the nadh dehydrogenase subunit 4 (nd4) mitochondrial gene was examined. an analysis of this fragment identified eight distinct haplotypes. the mean genetic diversity was high (h = 0.702; p = 0.01556). amova analysis indicated that most of the variation (67%) occurred within populations and the fst value (0.32996) was highly significant. fst values were significant in most comparisons among cities. the isolation by distance was not significant (r = -0.1216 and p = 0, 7550), indicating that genetic distance is not related to geographic distance. neighbor-joining analysis showed two genetically distinct groups within paraná. the dna polymorphism and amova data indicate a decreased gene flow in populations from paraná, which can result in increased vectorial competence.