MORPHOLOGICAL DETECTION OF X-CHROMOSOMES AND Y-CHROMOSOMES IN SMEARS AND PARAFFIN-EMBEDDED TISSUES USING A NONISOTOPIC IN-SITU HYBRIDIZATION TECHNIQUE (NISH)

Pharyngeal smears and paraffin-embedded tissue specimens (skeletal mus cle, kidney) obtained from 10 male and 10 female individuals were eval uated using non-isotopic in situ hybridization (NISH) with commercial X- and Y-specific biotinylated probes which recognize the pericentrome tric regions DXZ1 and DYZ1/DYZ3 of the X- and Y-chromosome, respective ly. The results provide evidence that the morphological sex determinat ion of a single cell can be performed by critical application of this staining method leading to one nuclear signal in ''male'' cells using the Y-specific probe whereas ''female'' cells are negative. In situ hy bridization of ''female'' tissues with an X-specific probe results reg ularly in 2 signals whereas ''male'' cells show only one spot in the n ucleus.