Localization of Y chromosome sequences and X chromosomal replication studies in XX males.
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.
Schempp
W
W
Institut für Humangenetik und Anthropologie der Universität, Freiburg i. Br., Federal Republic of Germany.
Müller
G
G
Scherer
G
G
Bohlander
S K
SK
Rommerskirch
W
W
Fraccaro
M
M
Wolf
U
U
D001192:Arylsulfatases / Q000235:genetics; D001483:Base Sequence; D002872:Chromosome Deletion; D015342:DNA Probes; D004303:Dosage Compensation, Genetic; D005819:Genetic Markers; D006801:Humans; D007621:Karyotyping; D008297:Male; D009693:Nucleic Acid Hybridization; D012729:Sex Chromosome Aberrations / Q000235:genetics*; D043266:Steryl-Sulfatase; D014960:X Chromosome; D014998:Y Chromosome
D015342:DNA Probes; D005819:Genetic Markers; D001192:Arylsulfatases; D043266:Steryl-Sulfatase