45S rDNA Localization For the Giant Ant Dinoponera gigantea With Evolutionary Inferences for the Dinoponera Genus (Formicidae: Ponerinae)

摘要

The Dinoponera genus is considered a relict group composed of six endemic South American species spread across five different biomes. These ants have an uncommon body size and share the absence of a morphologically differentiated queen in their nests.Cytogenetical data for that genus is already available for four species in which Dinoponera lucida is the most studied, however additional information about these giant South American ants is still needed. This work aimed to find the 45S rDNA genes throughout Dinoponera gigantea chromosomes using the FISH technique as a tool. Such data is particularly important for understanding chromosomal evolution in this ant genus. The analysis demonstrated several marks in different chromosomes of D. gigantea. Thecomparison between this result and the pattern found in D. lucida makes it possible to infer a chromosomal evolution model, taking into consideration some specific chromosomal rearrangements involving ribosomal genes, which led to the karyotypes of these two modern ants. This model can also be applied to the partially known species D. quadriceps and D. australis. Further cytogenetical information will be very useful for complete understanding of the taxohs evolution that could answer some important questions about the rising and dynamics of different South American biomes through Tertiary and Quaternary periods.