Comparative genomic hybridization (CGH) is an atomic cytogenetic technique for examining duplicate number varieties (CNVs) comparative with ploidy level in the DNA of a test contrasted with a reference test, without the requirement for refined cells. The point of this procedure is to rapidly and productively look at two genomic DNA tests emerging from two sources, which are frequently firmly related, in light of the fact that it is suspected that they contain contrasts regarding either gains or misfortunes of either entire chromosomes or subchromosomal areas (a segment of an entire chromosome). This procedure was initially created for the assessment of the contrasts between the chromosomal supplements of strong tumor and typical tissue, and has an improved goals of 5–10 megabases contrasted with the more conventional cytogenetic investigation strategies of giemsa banding and fluorescence in situ hybridization (FISH) which are constrained by the goals of the magnifying lens utilized.