Fluorescence in situ Hybridisation (FISH)
Fluorescence in situ hybridisation (FISH) uses fluorescently-labelled probes to detect specific gene sequences on the microscope slide. This can be used to confirm specific genetic abnormalities associated with a specific disease or phenotype. FISH can be used with metaphase chromosomes but is able to be applied to interphase (non-dividing cells) therefore cell culture is not always necessary.
Advantage of FISH-testing over conventional G-banded metaphase analysis
FISH testing can be applied to the non-dividing cell population therefore it is not necessary to culture the cells. This means that a result can be obtained within 24 hours (or less in some instances) if necessary.
Disadvantage of FISH-testing over conventional G-banded metaphase analysis
FISH-testing only permits comment on the presence or absence of specific loci or translocations. It is not a genomic-wide screen, therefore you MUST know the question that you would like answered. Dependent on the probe, it may only tell you that a gene rearrangement is present and not identify the partner gene.