For almost 60 years, scientists have tried to understand why DNA doesn't replicate wildly and uncontrollably every time a cell divides, which happens constantly. Without this process, we would die. These essential, ongoing cell divisions involve a cell copying its unique genetic material, DNA, and then forming new cells. Cells know exactly when and how to do this during the roughly 24 hours it takes to complete a division, and they also know what type of cell they should become: a liver cell, a brain cell, or a skin cell.