Scolomys, Anthony, 1924

Moreira, Camila Do Nascimento, Ventura, Karen, Percequillo, Alexandre Reis & Yonenaga-Yassuda, Yatiyo, 2020, A review on the cytogenetics of the tribe Oryzomyini (Rodentia: Cricetidae: Sigmodontinae), with the description of new karyotypes, Zootaxa 4876 (1), pp. 1-111 : 78

Scolomys sp.

Karyotype: 2n = 62 and FN = 80. Autosomal complement: one large subtelocentric pair, nine metacentric and submetacentric pairs medium to small decreasing in size, and 20 acrocentric pairs medium to small decreasing in size. Sex chromosomes: X, a submetacentric (the largest chromosome of the complement); Y, a large subtelocentric ( Fig. 20A ). C-banding metaphases exhibited blocks of constitutive heterochromatin on the pericentromeric region of all autosomes. The X chromosome presented an interstitial C-band on the short arm, a pericentromeric heterochromatic block and a conspicuous interstitial C-band on its long arm. The Y chromosome was almost entirely heterochromatic ( Fig. 20B ). G-banding was performed to allow the correct identification of all homologous pairs ( Fig. 20C ). FISH with telomeric sequences revealed signals exclusively at the ends of all chromosome arms and no interstitial signals were observed ( Fig. 20D ). This karyotype was basically the same reported by Patton & Silva (1995) for S. melanops with the presence of one additional acrocentric pair. Based only on the cytogenetic data these specimens seem to belongs to S. melanops and the difference in karyotype could have resulted from a fission-fusion involving an autosomal pair.

Figures

FIGURE 20. Karyotype of Scolomys sp., male with 2n = 62 and FN = 80. (A) Conventional staining (JAP 229); (B) C-banding (JAP 229); (C) G-banding (JAP 229); (D) Metaphase plate after fluorescent in situ hybridization with telomeric probe (left) and DAPI staining (right) (JAP 229).