Intragenomic heterogeneity of a ribosomal DNA spacer (ITS2) varies regionally in the neotropical malaria vector Anopheles nuneztovari (Diptera: Culicidae)

Abstract

We investigated intragenomic heterogeneity of ITS2 within twenty individual Anopheles nuneztovari (subgenus Nyssorhynchus) from five geographical localities in the neotropics (three from Brazil and one each from Colombia and Venezuela) by cloning and sequencing PCR-amplified copies of this spacer. Intragenomic heterogeneity was observed in thirteen of twenty mosquitoes of both sexes from all localities. As estimated by uncorrected P, however, mean sequence divergence was greater in mosquitoes from Brazil (PR = 0.0100, BL = 0.0196, AB = 0.0182) than in those from Venezuela (SO = 0.0026) or Colombia (SI = 0.0078). Sequence divergence per genome was significantly higher in mosquitoes from Brazil than in those from SO and SI. In fact, divergence among ITS2 variants within single mosquitoes from the Brazilian localities was often as great as that between localities. Similarly, the number of variants per mosquito was significantly greater in Brazil (maximum of six variants) than in both SO and SI (maximum of two variants). These results indicate that homogenization of ITS2 has proceeded to a greater extent in SO and SI than in the localities in Brazil. The differences in intragenomic heterogeneity between both SO and SI versus the Brazilian localities probably reflect either differences in population-level processes such as gene flow and genetic drift, or the fact that these localities may represent two or more cryptic species, as suggested by other studies.

Mitochondrial DNA Detects a Complex Evolutionary History with Pleistocene Epoch Divergence for the Neotropical Malaria Vector Anopheles nuneztovari Sensu Lato

“…[61][62][63] The samples from the Amazon Basin tended to have higher genetic diversity, in particular nucleotide diversity, than those from Bolivia/ Colombia/Venezuela. These differences were congruent with those of previous mitochondrial and nuclear gene studies 22,[25][26][27][28]64 and can be indicative of cryptic species, or possibly differences in effective population size ( N e) or other events related to the history of these populations. The highest genetic diversity was observed for localities in the central region of Amazonian Brazil.…”

Resurrection of Anopheles goeldii from synonymy with Anopheles nuneztovari (Diptera, Culicidae) and a new record for Anopheles dunhami in the Brazilian Amazon

“…nuneztovari A. Additionally, several clones showed a polymorphic A insertion after the G > T transversion in specimens with 3 GAs. The A insertion was absent in specimens from Suriname and Brazil published by Fritz et al (1994), but was observed by Onyabe and Conn (1999) in other Brazilian populations. These authors also showed that T (transversion) + A (insertion) is more frequent in specimens from states of Pará and Amazonas than in those from state of Rondônia (Brazil).…”

Speciation and phylogeography of the Southeast Asian Anopheles sundaicus complex

“…Ribosomal DNA is known to exhibit intra-individual variations in rDNA for species within the genus Anopheles (Onyabe and Conn, 1999;Beebe et al, 2001;Whang et al, 2002), and is currently used to differentiate species based on fixed, interspecific mutations (Collins and Paskewitz, 1996). Malaysian Borneo populations of the A. sundaicus complex exhibited a fixed deletion in position 532 of the ITS2 sequence.…”