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Vol. 45, No. 3-4, 1987
Issue release date: 1987
Cytogenet Cell Genet 1987;45:206–212
Original Article

A comparative chromosome banding analysis of the Ursidae and their relationship to other carnivores

Nash W.G.a · O’Brien S.J.b
aH & W Cytogenetic Services, Inc., Sterling, VA, and bLaboratory of Viral Carcinogenesis, National Cancer Institute, Frederick, MD


Trypsin G-banded karyotypes of eight species of Ursidae were prepared from retrovirus-transformed skin fibroblast cultures. The banding patterns of all bears are highly conserved, even though their diploid numbers range from 42 to 72. A comprehensive analysis of the homologous banding patterns within the Ursidae and with a hypothesized ancestral carnivore karyotype permitted the reconstruction of three significant chromosomal reorganization events that occurred during the evolution of the modern ursids. The first was a multichromosomal fissioning away from the biarmed (2n = 44) primitive carnivore karyotype, leading to six species of the Ursinae subfamily (2n = 78). The second was a comprehensive chromosome fusion in the lineage that led to the Ailuropodinae (giant panda) subfamily (2n = 44). The third event was a second, independent, but less extensive, centromeric fusion occurring in the line that led to the Tremarctinae (spectacled bear) subfamily (2n = 52). Ursidae karyotypes are not only highly conserved within the family but also exhibit extensive chromosome banding homology with other carnivore families.

 goto top of outline Author Contacts

Request reprints from: Dr. Stephen J. O’Brien, Laboratory of Viral Carcinogenesis, National Cancer Institute, Frederick, MD 21701-1013 (USA).

 goto top of outline Article Information

Received: 22 January 1987
Published online: May 09, 2008
Number of Print Pages : 7

 goto top of outline Publication Details

Cytogenetic and Genome Research

Vol. 45, No. 3-4, Year 1987 (Cover Date: 1987)

Journal Editor: Schmid M. (Würzburg)
ISSN: 1424–8581 (Print), eISSN: 1424–859X (Online)

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