a)Schematic drawing of a DNA chip 了一DNA Seg Spot containing copies Part of one of a single DNA DNA strand b) The detection of DNA-CDNA hy bridization air of CDNA complementary 2. CDNA from untreated CDNA chip DNA Cells are broken, RNa is extracted. the RNA is copied to produce complementary DNA(cDNA), and the CDNA is labelled with fluorescent tags. Example The cDNA represents genes that are of reactions active, that is, being converted to protein via RNA. c) Computer analysis of the binding of complementary uences can identify genes that respond to drug treatment Gene that strongly increased activity in treated cells o Gene that strongly decreased activity in treated cells a Gene that was equel,d cells in treated and untreate Gene that was inactive