GeneChip/microarray

Technique used to look for gene expression by analyzing the mRNA of many genes at once (looks for expression of genes of concern and other genes that may or may not be turned on by some stimuli)
In a well plate with lots of wells, cDNA that is complementary to mRNA to genes we want to know whether they are expressed or not is inserted into different wells. mRNA is extracted from an the control cells and from the experimental cells which are tagged with a fluorescent molecule. The tagged mRNA is allowed to interact with the cDNA in each well. The wells that light up signify mRNA hybridization, thus showing gene expression.