Cytogenetics of three species of Ameerega and study of the genetic variability of Ameerega flavopicta (Anura, Dendrobatidae)

Abstract

The taxonomy of dendrobatids was recently reviewed based on a robust phylogenetic analysis, which included a high number of species. The combined analysis of the cytogenetic data available and the phylogenetic relationships inferred allow suggesting that the presence of three pairs of small subtelocentric/telocentric chromosomes in the Ameerega flavopicta karyotype would be a derived condition in relation to the presence of four chromosome pairs with this characteristic (a condition observed in Ameerega picta, Ameeregahahneli and Ameerega trivittata).However, the available data are not sufficient to allow the recognition of the chromosomes possibly involved in the rearrangements that generated this karyotypic divergence. Another question related to A. flavopicta that deserves attention refers to the genetic variability among populations of this species. Although A. flavopicta mainly occupies open regions with Cerrado characteristics, some populations of this species were also found in restricted areas inside the Amazon forest that resemble Cerrado. It is still unknown whether these populations are isolated and in risk of extinction. In the present study, to investigate the possible chromosome rearrangements involved in the origin of the condition observed in the karyotype of A. flavopicta, we intend to describe the karyotype of A. braccata, a sister species of A. flavopicta, as well as to provide a molecular characterization of the karyotypes characterization of A. flavopicta and A. picta. Therefore, the sites of the 5S ribosomal genes and the chromosomal regions rich in AT or in CG will be localized. Tests using the chromosome painting technique, not usually employed to the cytogenetic study of anurans, will also be performed. To evaluate the influence of the landscape and the isolation of some populations in the genetic variability of A. flavopicta, different populations from Cerrado and from regions surrounded by forest will be analyzed using microsatellite sequences. Finally, the phylogenetic relationships of possible lineages of A. flavopicta will be inferred from mitochondrial and nuclear DNA sequences. (AU)