Submitted to: Colloquium on Domestic Animal Cytogenetics and Gene Mapping
Publication Type: Proceedings
Publication Acceptance Date: July 17, 1995
Publication Date: N/A
X-chromosome segment homologies among cattle, sheep and goats have been described by several laboratories. It can be summarized that G- and R-banding homologies for sheep and goats cover the entire length of the chromosome. However, X-chromosome banding similarities between cattle and the caprinae species have been reported to account from about 1/2 of the length of the chromosome to about 90%. The latter researchers point to the fact that no banding homology exist in the cattle X-chromosome for the caprinae X q42-q43 region. Interestingly, banding homologies for the cattle X q41-q43 that encompass the pseudoautosomal region have been found at X q1-q13 in the caprinae, that is, near the centromeric region. We have used the bovine Xp and Xq chromosome painting probes to assess the regions of homology between cattle and caprinea X-chromosomes. The bovine Xp painting probe was labeled with biotin-11-dUTP and detected with avidin-FITC. R-banding analysis showed that the entire bovine X-chromosome short arm is localized interstitially in the caprinae Xq comprising bands q35-q38, possibly including band q41. No bovine Xp signal was observed in the caprinae Xp. Two color simultaneous fluorescent in situ hybridization was carried out to show the extent of chromosome coverage and to define the interstitial nature of the bovine Xp homology. coverage and to define the interstitial nature of the bovine Xp homology. To do this, the bovine Xp painting probe was labeled with digoxigenin-11- dUTP and the bovine Xq painting probe with biotin-11-dUTP. Xp was detected with a TRICT-anti-digoxigenin Mab sandwich and the Xq was detected with avidin-FITC. Results showed that the bovine Xq homology extends from Xq11 to Xq34 and from Xq41 to Xq43 in caprinae.