Paper

Centric fusion differences among Oryx dammah, O. gazella, and O. leucoryx (Artiodactyla, Bovidae)
A.T. Kumamoto^a, S.J. Charter^a, S.C. Kingswood^a, O.A. Ryder^a, D.S. Gallagher, Jr.<sup>b

a</sup>Center for Reproduction of Endangered Species, Zoological Society of San Diego, San Diego, CA, and
^bDepartment of Animal Science, Texas A&M University, College Station, TX (USA)

Address of Corresponding Author

Cytogenet Cell Genet 1999;86:74-80 (DOI: 10.1159/000015416)

  Abstract.

G- and C-banded karyotypes of the genus Oryx were compared using the standard karyotype of Bos taurus. Chromosomal complements were 2n = 56 in O. gazellagazella, 2n = 58 in O. g. beisa and O. g. callotis, 2n = 56-58 in O. dammah, and 2n = 57-58 in O. leucoryx. The number of autosomal arms in all karyotypes was 58. Nearly all variation in diploid number was the result of three independent centric fusions, but one 2n = 57 specimen of O. g. gazella deviated from the normal complement of 2n = 56 due to XXY aneuploidy. A 2;17 centric fusion was fixed in O. g. gazella, whereas O. g. beisa and O. g. callotis lacked this fusion and had indistinguishable karyotypes. Oryx dammah was polymorphic for a 2;15 centric fusion, and O. leucoryx was polymorphic for an 18;19 centric fusion. The five Oryx taxa shared a fixed 1;25 centric fusion; the small acrocentric element involved in the 1;25 fusion was identified by fluorescence in situ hybridization using a cosmid specific to Bos chromosome 25. The X and Y chromosomes were also conserved among the five taxa. Oryx g. gazella differed from the other Oryx species because of the fixed 2;17 centric fusion. This difference reflects an apparently longer period of geographic isolation between O. g. gazella and other populations of Oryx, and it is consistent with the classification of O. gazella and O. beisa as distinct species (see Kingdon, 1997). The lack of monobrachial relationships among the Oryx taxa indicates that sterility barriers between species have not developed. Viability of hybrid offspring constitutes a threat to captive breeding programs designed for endangered species conservation; in the case of Oryx, the 2;15, 2;17, and 18;19 metacentrics could serve as marker chromosomes for assessing hybridization between certain Oryx taxa.

  Author Contacts

Request reprints from Andrea T. Kumamoto, Center for Reproduction ofEndangered Species, Zoological Society of San Diego, PO Box 120551,San Diego, CA 92112-0551 (USA); telephone: 619-557-3953;fax: 619-685-3244; e-mail: akumamoto@sandiegozoo.org.

  Article Information

Supported by the Sultanate of Oman and the Zoological Society of San Diego.

Received: Received 15 March 1999;
revision accepted 25 May 1999.
Number of Print Pages : 7
Number of Figures : 4, Number of Tables : 1, Number of References : 42