An unusual dicentric Y chromosome with a functional centromere with no detectable alpha-satellite.
We describe an unusual marker chromosome Y. This marker is present in 5% of the lymphocytes of a dysgenetic woman showing a mosaic karyotype 45,X/46,XY/47,XY+mar. Q-banding revealed that the marker was morphologically identical to the Y chromosome of the patient but presented the primary constriction in the heterochromatic region. C-banding confirmed that the heterochromatic region was C-positive; furthermore, it showed two spots in the euchromatic region in a position corresponding to that of the centromere in the normal Y. Fluorescence in situ hybridization with the centromere-specific probe pDP 97 and the pancentromeric alpha-satellite probe alpha 27 alpha 30 failed to detect any signal at the primary constriction site. To improve the characterization of the marker chromosome, hybridization was performed using pDP 105, a probe located on the short arm of the Y chromosome, together with chromosome-Y-specific paint-hybridizing to the single sequence spanning the Y short arm. In both cases, positive signals telomeric to the inactive centromere were observed. Possible mechanisms resulting in the formation of the marker chromosome are discussed.
Bukvic
N
N
Cattedra di Genetica Medica, Medicina del Lavoro, Bari, Italy.
Susca
F
F
Gentile
M
M
Tangari
E
E
Ianniruberto
A
A
Guanti
G
G
D000328:Adult; D001483:Base Sequence; D002503:Centromere / Q000235:genetics*; D002869:Chromosome Aberrations / Q000235:genetics*; D004276:DNA, Satellite / Q000235:genetics*; D005260:Female; D006801:Humans; D008969:Molecular Sequence Data; D014998:Y Chromosome
D004276:DNA, Satellite