Comparative genomic hybridization to detect variation in the copy number of large DNA segments.

Array comparative genomic hybridization (CGH) is an excellent tool to scan the genome for copy number variations (CNVs) when used conscientiously. This article is intended to provide an understanding of the basic principles of array CGH and the different options available to the user to design their array CGH experiments. Specifically, the six subsections discuss the different array platforms available, test and reference DNA preparation, reference DNA choice, the basics of hybridization, data processing, and our current understanding of CNVs in the human genome.