Detection of the X chromosomes in a Klinefelter boar using a whole human X chromosome painting probe.

In situ hybridization with an X chromosome specific painting probe can be used as a tool for studying the numerical and structural rearrangements of X chromosomes. The commercially available porcine specific X chromosome painting probe is still unable to reliably separate autosomes. However, due to across-species X chromosome homology, the human specific X chromosome painting probe can be used in the identification of X chromosomes in pig metaphases. The commercially available human X chromosome specific painting probe was hybridized to metaphase spreads in a Klinefelter boar with a 2n = 39, XXY karyotype to characterize the X chromosomes. Klinefelter syndrome with its effects on the male reproductive trait such as testicular hypoplasia, is under the genetic control of some sex-linked genes in the extra X chromosome which have escaped the X inactivation process. Chromosome analysis by chromosome painting using fluorescence in situ hybridization may in future be more widely used in veterinary medicine and the selection of breeding animals.