FISH analysis comparing genome organization in the domestic horse (Equus caballus) to that of the Mongolian wild horse (E. przewalskii)Myka J.L.a · Lear T.L.a · Houck M.L.b · Ryder O.A.b · Bailey E.a
aM.H. Gluck Equine Research Center, Department of Veterinary Science, University of Kentucky, Lexington, KY; bCenter for Reproduction of Endangered Species, Zoological Society of San Diego, San Diego, CA (USA)
Przewalski’s wild horse (E. przewalskii, EPR) has a diploid chromosome number of 2n = 66 while the domestic horse (E. caballus, ECA) has a diploid chromosome number of 2n = 64. Discussions about their phylogenetic relationship and taxonomic classification have hinged on comparisons of their skeletal morphology, protein and mitochondrial DNA similarities, their ability to produce fertile hybrid offspring, and on comparison of their chromosome morphology and banding patterns. Previous studies of GTG-banded karyotypes suggested that the chromosomes of both equids were homologous and the difference in chromosome number was due to a Robertsonian event involving two pairs of acrocentric chromosomes in EPR and one pair of metacentric chromosomes in ECA (ECA5). To determine which EPR chromosomes were homologous to ECA5 and to confirm the predicted chromosome homologies based on GTG banding, we constructed a comparative gene map between ECA and EPR by FISH mapping 46 domestic horse-derived BAC clones containing genes previously mapped to ECA chromosomes. The results indicated that all ECA and EPR chromosomes were homologous as predicted by GTG banding, but provide new information in that the EPR acrocentric chromosomes EPR23 and EPR24 were shown to be homologues of the ECA metacentric chromosome ECA5.
© 2003 S. Karger AG, Basel
Request reprints from Dr. Teri L. Lear, M.H. Gluck Equine Research Center
Department of Veterinary Science, University of Kentucky
Lexington, KY 40546-0099 (USA); telephone: 859-257-4757
fax: 859-257-8542; e-mail: email@example.com
Supported by a graduate fellowship from the Geoffrey C. Hughes Foundation to J.L.M. Additional support was provided by the Morris Animal Foundation.
Received 1 August 2003;
revision accepted 2 September 2003.
Number of Print Pages : 4
Number of Figures : 1, Number of Tables : 1, Number of References : 35
Cytogenetic and Genome Research
Formerly ‘Cytogenetics and Cell Genetics’
Vol. 102, No. 1-4, Year 2003 (Cover Date: 2003)
Journal Editor: H.P. Klinger, Bronx, N.Y.; M. Schmid, Würzburg
ISSN: 1424–8581 (print), 1424–859X (Online)
For additional information: http://www.karger.com/journals/cgr