In situ hybridization--application to gene localization and RNA detection.

In situ hybridization offers a direct approach for localization and quantitation of nucleic acid sequences in cellular preparations. Recent improvements in technology and methodology make possible the detection of DNA and RNA of relatively low copy number. For example, development of in situ hybridization methods for detection of single copy DNA sequences on mitotic chromosomes has led to general use of this technique for gene mapping of the human genome. More recently, improvements in methodology for detection of low abundancy RNA make possible a facilitated analysis of gene expression, both from cellular genes and exogenous sequences, such as viral genomes. In situ hybridization is now a powerful method for studying nucleic acid organization and function in normal cells, as well as in malignant cells, which should contribute to better understanding of the cell transformation process.