Principle of Digital Imaging Microscopy

A challenging problem of in situ hybridization is to visualize then localize genes or specifie sequences within the interphase nuclei or on chromosomes, as we now have at our disposai a large panel of probes. In addition, methods for probe labeling are continuously being improved to allow increased efficiency of in situ hybridization. A considerable advance was recently achieved in chromosome and chromatin mapping by taking advantage of chromatin decondensation (1 , 2 ) and multicolor fluorescence labeling (3 –6 ). Sequences separated by less than 10 kb could be resolved in that way (1 , 2 ).