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Variability in the nucleolus organizer regions of domestic pig chromosomes (Sus scrofa)

Jorge Luis Armada; Ana Clécia Vieira Santos

Universidade Federal Rural do Rio de Janeiro , 23851-970 Rio de Janeiro, RJ, Brasil. Send correspondence to J.L.A.

ABSTRACT

NOR-banded metaphase chromosomes were characterized in the domestic pig (Sus scrofa). Only the no. 10 pair showed NOR banding in the region adjacent to the centromere of the short arm, following silver staining. NOR region association at metaphases was not observed, though intraspecific size variation of labeled NORs was seen. Polymorphism was evident in two animals in which the NOR band was duplicated. A possible association of this polymorphism with reproductive problems detected in a female is discussed.

Keywords: nucleolus; domestic pig; chromosomes.

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