Comparação cariotípica e genômica em mico-leão (Leontopithecus, Platyrrhini, Primates)

Abstract

The genus Leontopithecus is composed of four species, all considered endangered by the IUCN and endemic to the Atlantic Forest. The four species of the genus have the same diploid number 2n = 46 and fundamental number of autosomal arms FN = 74. L. rosalia and L. chrysomelas have been karyotypically better studied than L. chrysopygus and L. caissara. In order to obtain more information about this endangered genus, we comparatively analyzed the karyotypes of L. chrysopygus, L. rosalia, and L. chrysomelas based on GTG-, CBG-banding, silver staining of the nucleolus organizer regions (Ag-NORs), fluorescent in situ hybridization (FISH) with telomeric sequences and rDNA 18S as probes, and genomic in situ hybridization (GISH). Our results revealed very similar karyotypes, with some differences between the CBG banding patterns, Ag-NORs distribution and FISH with rDNA 18S probe. GISH experiments between L. rosalia and L. chrysopygus revealed some species-specific heterochromatic regions. We also investigated two satellite DNAs, the alpha and the CarB present in the genome of L. rosalia, which could be related to the chromosomic differences observed between the Leontopithecus species. Our results indicate that a more detailed analysis of the repetitive sequences shall provide a better understanding of the chromosome evolution in the genus Leontopithecus.