Euryoryzomys nitidus

Euryoryzomys nitidus

Karyotype: 2n = 80 and FN = 86. Autosomal complement: four small metacentric pairs, and 35 acrocentric pairs (one distinctly large and the remaining large to small decreasing in size). Sex chromosomes: X, a very large subtelocentric; Y, a small acrocentric (Gardner & Patton 1976, pp. 4, Fig. 1E; Patton et al. 2000). A different morphology of sex chromosomes was reported by Volobouev & Aniskin (2000), a submetacentric X and a metacentric Y chromosome. C-banding metaphases exhibited blocks of constitutive heterochromatin on the pericentromeric region of all autosomes. The short arm of X and the Y were entirely heterochromatic. G-banding was also performed (Volobouev & Aniskin 2000). FISH with telomeric sequences revealed signals exclusively at the ends of all chromosome arms and no interstitial signals were observed (Silva et al. 2000).