Can genes be turned on and off in cells?

Yes, genes are able to be turned on and off through the process of gene regulation. Gene regulatory proteins control which genes are activated or deactivated in an organism. They vary between cell types, determining the specific patterns of gene expression that give each cell its distinct features. Gene regulation mainly happens during transcription. This regulation is often driven by signals from the environment or neighboring cells. These signals trigger the activation of specific proteins known as transcription factors. These factors then control whether a gene is turned on or off, influencing the production of mRNA from the gene's DNA sequence. During development, genes are activated or deactivated in unique patterns to give different cell types, like brain cells, liver cells, or muscle cells, their distinct characteristics. Additionally, gene regulation enables cells to promptly respond to changes in their surroundings.