fluorescence in situ hybridization: translation
(= FISH; chromosome painting)
Technique of directly mapping the position of a gene or DNA clone within a genome by in situ hybridization to metaphase spreads, in which condensed chromosomes are distinguishable by light microscopy. The DNA probe is labelled with a fluorophore, and the hybridization sites visualized as spots of light by epifluorescence. Frequently, several probes can be used at one time, to mark specific chromosomes with different coloured fluorophores (‘chromosome painting’).