Localization of Y chromosome sequences and X chromosomal replication studies in XX males

Hum Genet. 1989 Jan;81(2):144-8. doi: 10.1007/BF00293890.


By in situ hybridization, Y-specific DNA sequences were localized on Xp22.3-Xpter of one of the two X chromosomes in all of eleven XX males studied. In nine of the cases the presence of the Y-specific DNA did not affect random X inactivation in fibroblasts. Fibroblasts of the other two cases showed a preferential inactivation of the Y DNA-carrying X chromosome. In only one of these two exceptions blood lymphocytes could also be studied, and here, random inactivation of the Y DNA-carrying X chromosome occurred. Furthermore, the gene dosage of steroid sulfatase (STS) was examined by Southern blot analysis. In ten of the cases including the one showing random X-inactivation in lymphocytes but not in fibroblasts, a double dosage of the STS gene is present. The remaining case with non-random inactivation shows a single STS gene dosage. This case was reported previously to have STS enzyme activity in the male range. It is assumed that, as a consequence DNA sequences may result in the preferential inactivation of the Y DNA-carrying X chromosome.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arylsulfatases / genetics
  • Base Sequence
  • Chromosome Deletion
  • DNA Probes
  • Dosage Compensation, Genetic
  • Genetic Markers
  • Humans
  • Karyotyping
  • Male
  • Nucleic Acid Hybridization
  • Sex Chromosome Aberrations / genetics*
  • Steryl-Sulfatase
  • X Chromosome*
  • Y Chromosome*


  • DNA Probes
  • Genetic Markers
  • Arylsulfatases
  • Steryl-Sulfatase