Gene activation

the process of activation of a gene so that it is expressed at a particular time, giving rise to the corresponding RNA and (for protein-encoding genes) protein product.

Description
The process of gene activation and deactivation is crucial in growth and development. While (almost all) cells of the body contain the same set of genes, not all of them are expressed in a given cell at any one time. For instance, stem cells express a wide complement of genes, while terminally differentiated cells in different organs experience large-scale deactivation of genes and activation of particular sets of genes specific to the cells' respective roles.