A new karyotype for Rhipidomys (Rodentia, Cricetidae) from Southeastern Brazil
Ana Heloisa de Carvalho1, Maria Olímpia Garcia Lopes, Marta Svartman
1Universidade Federal de Minas Gerais, Laboratório de Citogenética Evolutiva, Departamento de Biologia Geral, Instituto de Ciências Biológicas, Av. Antônio Carlos, 6627 - Pampulha, 31270-910, Belo Horizonte, Brazil.
Abstract:
In this work we present a new karyotype for Rhipidomys Tschudi, 1845 (Cricetidae, Rodentia) from Brazil. Our chromosome analyses included GTG- and CBG-banding patterns, the localization of the nucleolus organizer regions after silver staining (Ag-NORs) and fluorescence in situ hybridization (FISH) with a telomere probe. The new karyotype is composed of 44 chromosomes and has a fundamental number (number of autosomal arms) of 48. Most Rhipidomys species already karyotyped presented similar complements with 2n=44, but their fundamental numbers varied from FN=46 to 80, a variation that has been mainly attributed to pericentric inversions. The comparison of this new karyotype to those of other Rhipidomys already reported allowed us to conclude that it is a distinctive chromosome complement, which can be of great use as a tool for the very complicated taxonomic identification in this genus.
