Intragenomic heterogeneity of internal transcribed spacer rDNA in neotropical malaria vector Anopheles aquasalis (Diptera: Culicidae).

Intragenomic heterogeneity of the internal transcribed spacer (ITS) array was investigated in Anopheles aquasalis Curry mosquitoes from two geographic locations in each of Brazil and Venezuela, and one in Suriname. Polymerase chain reaction-amplified copies of the ITS were cloned and sequenced. The length of the entire array ranged from 782 to 990 bp, with most variation due to microsatellite insertions in ITS1. We detected 40 different ITSL sequences and 15 different ITS2 sequences of the 71 to 72 clones examined. The sequence divergence within localities ranged from 0.002 to 0.043 for ITS1 and from 0 to 0.006 for ITS2. Point mutations were common to both spacer regions, but dinucleotide microsatellite repeats were restricted to ITS1. Sequences from neither ITS1 nor ITS2 had a diagnostic distribution or were informative in distinguishing these populations, providing additional support for the status of An. aquasalis as a single species.