Association mapping of segregating sites in the early trypsin gene and susceptibility to dengue-2 virus in the mosquito Aedes aegypti

Insect Biochem Mol Biol. 2005 Jul;35(7):771-88. doi: 10.1016/j.ibmb.2005.02.015. Epub 2005 Mar 31.


Evidence suggests that midgut trypsins in Aedes aegypti condition the mosquito's ability to become infected with the dengue-2 flavivirus (DEN2). The activity of early trypsin protein peaks approximately 3 h after blood feeding and then drops within a few hours. We use association mapping to test the hypothesis that segregating sites in early trypsin condition midgut susceptibility to DEN2 virus. A total of 1642 females from throughout Mexico and the southern US were fed an artificial blood meal containing DEN2. After 2 weeks, mosquito heads and midguts were tested for DEN2. Mosquitoes with an infected head were classified as susceptible, those without a midgut infection had an infection barrier, and those with an infected gut but no head infection had an escape barrier. The early trypsin gene was amplified in two overlapping pieces from each mosquito and analyzed for single strand conformation polymorphisms (SSCPs). Unique SSCP genotypes were sequenced and 90 segregating sites were found. The dataset was divided into the four geographic regions within which Ae. aegypti is panmictic in Mexico. Heterogeneity chi2 analyses between alleles or genotypes and infection phenotypes demonstrated significant associations but allelic and genotypic effects were inconsistent among geographic regions. No consistent associations were found between segregating sites in early trypsin and susceptibility to DEN2 in Ae. aegypti in Mexico.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Aedes / genetics*
  • Aedes / immunology*
  • Aedes / virology
  • Alleles
  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Chromosome Mapping
  • Dengue Virus / immunology*
  • Digestive System / virology
  • Genetic Linkage
  • Genetic Variation
  • Genotype
  • Insect Vectors / genetics*
  • Insect Vectors / immunology*
  • Insect Vectors / virology
  • Molecular Sequence Data
  • Phenotype
  • Quantitative Trait, Heritable
  • Time Factors
  • Trypsin / genetics*


  • Trypsin