A regulatory gene is a gene which determines whether or not genes will be expressed. Also known as regulator genes, some regulatory genes are concerned with a specific gene, while others can handle a group of related genes. These genes are produced by all organisms, and are an important part of the system of checks and balances used to moderate genetic expression so that an organism operates effectively and efficiently.
In some cases, a regulatory gene acts as an activator, turning a gene or group of genes on so that expression can occur. The regulatory gene may respond to environmental pressures, as when an activator in a bacterium activates a gene for antibiotic resistance when the organism is around antibiotics. In complex multicellular organisms, regulatory genes are involved in the process of cell differentiation, determining what a cell will develop into. This allows organisms to have great diversity in cell types, making everything from neurons to skin cells.
Other genes act as repressors, turning genes off so that they cannot express. Like activators, suppressors can go into action in response to a number of different things, including environmental pressures and the needs of embryonic development. These genes can do things like preventing RNA transcription so that genetic material cannot be used. This type of regulatory gene may also act to suppress a harmful gene, keeping an organism healthy.
Like other genes, regulatory genes contain information which is used to code proteins. They are transcribed into RNA, which is used by the cells to build the proteins these genes are designed to express. Once created, the protein can act in a variety of ways on the genetic material inside the cell, depending on what it is intended to do. For example, a regulatory gene might make a protein which locks onto a section of DNA so that it cannot be transcribed.
Identification of regulatory genes is done by studying the genome, finding specific genes, looking at the proteins which they code for, and studying the effect of these proteins. Researchers working with organisms such as fruit flies can do things like turning genes off or on and then observing the results to learn more about what these genes do. In organisms like humans, where genetic manipulation is not considered ethical, researchers can compare genetic information between many humans to look for commonalities and differences, using this information to narrow down the function of specific genes.