Interphase FISH

Interphase fluorescence in situ hybridization (FISH) is a modification of FISH analysis that allows high resolution analysis because probes are hybridized to minimally condensed interphase chromosomes. In the interphase nucleus, chromosomal structures cannot be discerned and only the hybridized probe will light up. The cell nucleus in this figure was hybridized with a probe for a region on the X chromosome (red) and one for an area on the Y chromosome (green). The presence of three separate signals indicates that this individual has two X chromosomes (red) and one Y chromosome (green). This chromosomal abnormality causes Klinefelter syndrome.