Chromosomal rearrangements drive diversity in arboreal rodents of the genus Oecomys.

Oecomys (Rodentia, Sigmodontinae, Oryzomyini) is a taxonomically complex and cytogenetically diverse genus with a controversial intraspecific phylogenetic relationship. Karyotypic analyses, using whole chromosome probes from Hylaeamys megacephalus (HME, Sigmodontinae, Oryzomyini) in some taxonomic lineages of this genus have detected the rearrangements that shaped their karyotypes, in addition to revealing relevant insights into the taxonomic status of these taxa. Thus, to investigate the chromosomal evolution of the genus, we characterized the karyotype of Oecomys rutilus (ORU) with HME probes, establishing chromosomal homology maps with the karyotypes of other congeners.

Comparative genomic mapping reveals mechanisms of chromosome diversification in Rhipidomys species (Rodentia, Thomasomyini) and syntenic relationship between species of Sigmodontinae.

Rhipidomys (Sigmodontinae, Thomasomyini) has 25 recognized species, with a wide distribution ranging from eastern Panama to northern Argentina. Cytogenetic data has been described for 13 species with 12 of them having 2n = 44 with a high level of autosomal fundamental number (FN) variation, ranging from 46 to 80, assigned to pericentric inversions. The species are grouped in groups with low FN (46-52) and high FN (72-80).