Resumo

URENA VARGAS, Lisbeth Katherine  e  LOPEZ ORTIZ, Juan Bautista. CYTOGENETIC CHARACTERIZATION WITH R-REPLICATIVE BANDS OF TAIL GUAGUA (DYNOMIS BRANICKII). Rev. Fac. Nac. Agron. Medellín [online]. 2010, vol.63, n.1, pp.5355-5362. ISSN 0304-2847.

Dinomys branickii is also called tail guagua or "Pacarana", is the second biggest living rodent of the world. Due to man factors this rodent is actually endangered. According to hair colour and height have been proposed the existence of three subspecies: Dinomys pacarana in Brasil, Dinomys gigas in Colombia and Dinomys branickii occidentalis in Ecuador and Colombia. Eventhough morphological rating there have been made, no other cytogenetic reports exist to let know whether the three subspecies have same karyotype. The goal of this work was to make the karyotype of Dynomis branickii using R-replicative bands through the incorporation of 5-bromo-2´-deoxyuridine (BrdU). The cytogenetic study showed a chromosome number 2n=64 and a fundamental number FN=98. The result of the karyotype was organized in three groups as: A group with 1 chromosome metacentric pair and 11 chromosome submetacentric pairs, B group with 5 metacentric pairs, C group with 14 chromosome subtelocentric pairs, and sexual chromosome pair XY, where X chromosome is submetacentric and Y subtelocentric. The ideogram was made with metaphase chromosomes on third stage of replication. The R-replicative banding revealed: the inactive behavior of the X chromosome like other mammalian females, and the smallest size in whole genome and late replication of the Y chromosome. This cytogenetic evidence showed the karyotype and ideogram of this specie for first time, which supports future cytogenetic knowledge of other subespecies related.

Palavras-chave : Karyotype; R-replicative bands; rodent; chromosomes; ideogram.

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