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Supernumerary chromosomes in Holochilus brasiliensisand comparative cytogenetic analysis with Nectomys squamipes (Cricetidae, Rodentia)

Yatiyo Yonenaga-Yassuda^I; Rosany Carvalho do Prado^I; Dalva A. Mello^II

^IDepartamento de Biologia, Instituto de Biociências, Universidade de São Paulo, Caixa Postal 11461, 05499 São Paulo, SP, Brasil. Send correspondence to Y.Y.-Y.
^IIDepartamento de Ciências da Saúde, Universidade Federal de São Carlos, Caixa Postal 676. 13560 São Carlos, SP, Brasil

ABSTRACT

In Holochilus brasiliensis, a colony originally collected at São Bento, State of Maranhão, Brazil different diploid numbers (2n = 56, 57 and 58) were found due to submetacentric supernumerary chromosomes (SNC) from 0 to two. G-, C- and R-banding patterns and silver staining of the nucleolar organizer regions (NORs) are presented. The heterochromatic nature of SNC was determined after C-banding and 5-BrdU incorporation. A comparative analysis of G-banding of H. brasiliensis (2n = 58) and Nectomys squamipes (2n = 57) showed almost complete homology with some minor rearrangements.

Keywords: chromosomes; Holochilus brasiliensis; cytogenetic; Nectomys squamipes.

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