IN CGH, the genomic DNA from the specimen and the control DNA extracted from a person with a normal karyotype 46,XX or 46,XY are differentially labeled with green and red fluorochromes, respectively, jumbled in equal amounts and co hybridized to reference human metaphase chromosomes Fig. 16. 10. The relative difference in DNA content material between the conventional and specimen DNA is represented by a difference in the fairway/red fluorescence ratios. For instance, if the chromosomal fabric is existing in identical copy numbers in both the reference and the specimen genome, the observed fluorescence is a blend of an equal contribution of red and green fluorescence. If chromosomes are lost or chromosomal subregions are deleted in the specimen genome, the ensuing color is shifted to red.