ABSTRACT
Using total genomic DNA (gDNA) as a probe for in situ hybridization (ISH) experiments is a modifi ed FISH (fl uorescence in situ hybridization) technique that becomes an increasingly relevant approach in non-clinical research, including fi sh molecular cytogenetics. GISH (genomic in situ hybridization) and CGH (comparative genomic hybridization) are two basic types of ISH experiments using gDNA as probes. These methods utilize DNA-DNA hybridization and sequence similarities to visualize genome specifi c DNA on metaphase spreads. They allow for comprehensive analysis of entire genomes:
1. In GISH the labelled gDNA of one organism is used as a probe and hybridized to target chromosomal DNA of another, usually a hybrid organism, to discriminate chromosomes originating in one of the parental species.
