Multiplex FISH

With this approach (M-FISH), sets of chromosome-
specific DNA probes, each labeledwith its
own combination of DNA-binding fluorescent
dyes, are hybridized to metaphase chromosomes.
For each chromosome type, a specific
multicolor bar code is constructed by using
different YAC clones (yeast artificial chromosomes)
containing the DNA probes to be applied.
Only five different fluorophores are necessary
for image analysis by epifluorescence
microscopy using a charge-coupled device
(CCD) camera to generate a composite image of
each chromosome in a pseudocolor visualized
by appropriate software. The karyotype
generated in this way is composed of the 22
pairs of autosomes and the X and the Y each in a
different color.