Thomas More College1, Biology, Crestview Hills, KY 41017 University of Kentucky2, Veterinary Science, Lexington, KY 40546 Center for Reproduction of Endangered Species3, Zoological Society of San Diego, San Diego, CA 92101
The onager [E. hemionus onager, EHO] and the domestic horse [E. caballus, ECA] have evolved over the course of 3.7 million years. The closely related EHO and ECA have diploid chromosome numbers of 2n=56 and 2n=64, respectively. Comparative gene mapping was done by FISH [fluorescent in-situ hybridization] mapping of 11 BAC probes containing ECA genes to EHO metaphase chromosomes. FISH analysis resulted in the successful hybridization of 5 probes (CRTAP [ECA 16q21], FBX03 [ECA 12q14], ZMFU69274 [ECA 16q23-q24], SOD1 [ECA 26q15], and MUT [ECA 20q21]) to one arm [a p arm or a q arm] of 5 different EHO metaphase chromosome. Also three different pairs of BAC probes from 6 ECA chromosome arms BASP1 [ECA 20q21] and GNMT [ECA 24q16], GLG1 [ECA 3p13-p12] and CTLA3 [ECA 21q13-q14], ALPL [ECA 2p14] andEIF3S8 [ECA 13q12-q13] hybridized to three different EHO chromosomes with one probe hybridizing to the p arm and the other to the q arm. These results add to the current low density comparative gene map of the onager. Since the BAC probes contained ECA genes, these results contribute to greater understanding of the chromosome evolution of the equid species and the ancestral equid genome organization.
[Abstract (DOC)]