Reporter gene
In molecular biology, a reporter gene (often simply reporter) is a gene that researchers attach to another they wish to study in cell culture, animals or plants. Many of the techniques used for engineering a foreign or modifed gene into an organism work only in a very small percentage of individuals. Researchers use a reporter to easily identify those that have taken up the gene, or which have incorporated it in the desired way into their chromosomes. A common reporter is the gene that encodes jellyfish green fluorescent protein, which causes cells that express it to glow green under UV light.
Reporter genes are often placed downstream of the promoter region and in the proximity of the gene of interest to ensure that they are expressed together and not separated by crossover events.