X-CHROMOSOME EVOLUTION IN THE SUNI AND ELAND ANTELOPE - DETECTION OF HOMOLOGOUS REGIONS BY FLUORESCENCE IN-SITU HYBRIDIZATION AND G-BANDING

Comparative cytogenetics and fluorescence in situ hybridization (FISH) were used to track structural rearrangements in the X chromosomes of two African antelope species, the eland (Taurotragus oryx; tribe Trage laphini) and the suni (Neotragus moschatus; tribe Neotragini). Using t wo microdissected cattle chromosome painting probes (one specific for Xp-containing sequences corresponding to Xp24-->p12 of the cattle X, a nd one specific for Xq-containing sequences corresponding to Xq12-->qt er), we show that intrachromosomal rearrangements distinguish the X ch romosomes of these species. Furthermore, there is clear evidence that, superimposed on this background of intrachromosomal evolutionary chan ge, the sequences contained in the cattle Xp painting probe appear to have moved as a complete unit during the repatterning of the bovid X. Although we are unable to infer the order of the rearranged chromosoma l segments, given the large regions of homology detected by the chromo some paints, we nonetheless believe that this approach (combining conv entional and molecular cytogenetic studies on the X chromosome) will p rove useful for inferring phylogenetic relationships in the family Bov idae, particularly as more probes become available.