Increased FISH efficiency using APC probes generated by direct incorporation of labeled nucleotides by PCR

Probes of various sizes from the adenomatous polyposis coli gene (APC) were directly biotinylated by polymerase chain reaction (PCR) from genomic DNA. PCR labeling gave high efficiency in detection of fluorescence in situ hybridization (FISH) signals. Probes as small as 250 base pairs could be visualized through a fluorescence microscope without any image processing.