Comparative Genomic Hybridization

Comparative genomic hybridization (CGH ) allows a genome-wide survey of the relative copy number of tumor DNA in a single hybridization. The tumor-cell DNA (Test DNA) is hybridized together with a sex-matched normal DNA (Reference DNA) onto normal metaphase spreads. Test DNA and Reference DNA are labeled with fluorochrome-conjugated reagents of different color, thereby allowing the detection of genetic imbalance in the abnormal cells.