I.DNA Microarray Purposes So why do we use DNA microarray? To measure changes in gene expressionlevels-two samples'gene expression can be compared from different samples,such as from cells of different stages of mitosis. To observe genomic gains and losses.Microarray Comparative Genomic Hybridization(CGH) To observe mutations in DNA.Purposes • So why do we use DNA microarray? – To measure changes in gene expression levels – two samples’ gene expression can be compared from different samples, such as from cells of different stages of mitosis. – To observe genomic gains and losses. Microarray Comparative Genomic Hybridization (CGH) – To observe mutations in DNA. I. DNA Microarray