Answer:
All organisms must regulate gene expression by turning genes on and off different cells at different times. In prokaryotic cells, related genes may be organized into operons , which can be turned on and off as a single unit. Eukaryotes have more complex modes of control, including the packing of chromosomes, RNA slicing (which can produces several mRNAs from a single gene), and the control of translation.
An understanding of gene regulation mechanisms has led to several interesting and important applications. For example, the loss of gene regulation can result in cancer, or out-of-control cell growth. And reproductive cloning can produce new live individuals, while therapeutic cloning can produce potentially therapeutic stem cells.