DNA degradation of Anopheles darlingi collected at high relative humidity and preserved in isopropanol

Anopheles darlingi mosquitoes, exposed to variable relative humidity (RH) in the field, were preserved during transportation to the laboratory using two different methods: 100% isopropanol at ambient temperature or frozen in liquid nitrogen or dry ice. The DNA isolated from samples collected at RH greater than 91% and preserved in isopropanol was degraded, while DNA isolated from insects kept in liquid nitrogen or dry ice maintained its integrity when collected under conditions of up to 95% RH.

Population genetic structure of the dengue mosquito Aedes aegypti in Venezuela

The mosquito Aedes aegypti is the main vector of dengue in Venezuela. The genetic structure of this vector was investigated in 24 samples collected from eight geographic regions separated by up to 1160 km. We examined the distribution of a 359-basepair region of the NADH dehydrogenase subunit 4 mitochondrial gene among 1144 Ae. aegypti from eight collections. This gene was amplified by the polymerase chain reaction and tested for variation using single strand conformation polymorphism analysis. Seven haplotypes were detected throughout Venezuela and these were sorted into two clades. Significant differentiation was detected among collections and these were genetically isolated by distance.