Free Chromatin Mapping by FISH

Different strategies have been introduced to facilitate characterization of complex genomes; the techniques include molecular cloning, agarose gel electrophoresis and blot-hybridization analysis, DNA sequencing, construction of somatic cell hybrid lines, in situ hybridization, as well as genetic (linkage) analysis. Because of their wide application, numerous improvements have been made in each of these areas in recent years, for example, the use of pulsed-field gel electrophoresis (PFGE), yeast artificial chromosome (YAC), and fluorescence in situ hybridization (FISH) (1 –4 ). Obviously, no single method can provide all the information required for detailed analysis of genomes with greater than several billion base pairs (bp) and each method has its limitation in range of resolution. A combination of different techniques is therefore necessary for any large-scale gene mapping endeavors.