Oligonucleotide Primed in Situ DNA Synthesis (PRINS): An Alternative to in Situ Hybridization for Gene Mapping and the Investigation of Genome Organiz

The technique of in situ hybridization has come of age, it being more than 21 years since the first descriptions of the procedure were published (1 ). In that time, the capabihties of the method have expanded enormously. In the early years, the sensitivity (minimum size of target capable of being detected) was restricted to highly repeated DNA sequences, such as satellite DNAs, and detection was exclusively by autoradiography of radioisotopic label (e.g., ref. 2 ). In time, it became possible to map unique sequences (e.g., ref. 3 ), but this was a tedious procedure involving the analysis of grain distribution over large numbers of metaphase spreads, in order to distinguish specific hybridization signal from background grains.