Morphological detection of X- and Y-chromosomes in smears and paraffin-embedded tissues using a non-isotopic in situ hybridization technique (NISH)

Pharyngeal smears and paraffin-embedded tissue specimens (skeletal
muscle, kidney) obtained from 10 male and 10 female individuals
were evaluated using non-isotopic in situ hybridization (NISH) with
commercial X- and Y-specific biotinylated probes which recognize
the pericentromeric regions DXZ1 and DYZ1/DYZ3 of the X- and
Y-chromosome, respectively. The results provide evidence that the
morphological sex determination of a single cell can be performed
by critical application of this staining method leading to one
nuclear signal in ldquomalerdquo cells using the Y-specific probe
whereas ldquofemalerdquo cells are negative. In situ hybridization
of ldquofemalerdquo tissues with an X-specific probe results
regularly in 2 signals whereas ldquomalerdquo cells show only one
spot in the nucleus.