Comparative karyotypic analysis of two Calomys species (Rodentia, Cricetidae) from Central Brazil

SUMMARY

The karyotypes of Calomys callosus expulsus (2n = 66; FN = 68) and C. laucha tener (2n = 66; FN = 66) collected in the Federal District, State of Goiás, Central Brazil, were analyzed. G-banding evidenced similarity between both karyotypes and a pericentric inversion in the largest pair of autosomes, which accounts for the variation in FN. C-banding revealed a difference in the contents of constitutive heterochromatin, which is higher in C. laucha tener. The mechanisms of interspecific karyotypic divergence is discussed.