Non-radioactive in situ hybridization of DNA probes to chromosomes and nuclei. A comparison of techniques.

We have used a moderate repeat probe and a number of single copy DNA probes of varying sizes to compare different approaches to non-radioactive in situ hybridization. We have compared the ease and speed of the methods, the sensitivity, resolution, reproducibility, the availability and costs of reagents, and the potential for clinical application. Following biotinylation or mercuration, the probes were hybridized to human metaphases and nuclei and detected by different affinity systems. Visualization of signals was by brightfield, phase contrast, fluorescence or reflection contrast microscopy. As a result of our study, we recommend two simple and reliable methods using the biotinylation approach with either the avidin-peroxidase conjugate and diaminobenzidine detection and reflection contrast microscopy, or the streptavidin-alkaline phosphatase conjugate and bromochlorodinolyl phosphate nitroblue tetrazolium chloride detection using phase contrast microscopy.