(T2AG3)n telomeric sequence hybridization indicating centric fusion rearrangements in the karyotype of the rodent oryzomys subflavus.

Chromosome preparations of 30 specimens of Oryzomys subflavus trapped in eight Brazilian localities were C-, and G-banded and analyzed by fluorescence in situ hybridization (FISH). Two karyotypes were found, 2n = 50/FN = 64, at three coastal localities of the Atlantic Forest domain, and 2n = 58/FN = 70 at two sites located in the Cerrado biome, Brazil Central. Two fluorescence in situ hybridization (FISH) patterns of the telomeric sequence (T2AG3)n were observed: in both karyotypes the probes hybridized to the telomeres of all chromosomes and also a hybridization signal in the centromeric regions of two autosome pairs was seen in the 2n = 50 karyotype. These results, together with the occurrence of other diploid numbers described in the literature, suggest that 0. subflavus is a complex species, bearing fusion/fission rearrangements proper to the different biomes which it inhabits.