Instant PRINS: a rapid method for chromosome identification by detecting repeated sequences in situ.

We describe a method for labeling specific chromosomes in situ by oligonucleotide-primed synthesis and incorporation of fluorochrome-labeled dUTP, together with an accelerated protocol for the reaction. The combination of the two developments produces extremely rapid results, in some cases taking less than 5 min for the complete process. The significance of this development for clinical diagnosis is discussed.