When something goes wrong during DNA replication, cells call their own version of 911 to pause the process and fix the problem -- a failsafe that is critical to maintaining health and staving off disease. Now, scientists have for the first time revealed how a key piece of this repair process -- appropriately called the 911 DNA checkpoint clamp -- is recruited to the site of DNA damage. The findings illuminate new insights into the way cells ensure genetic instructions are properly passed from one generation of cells to the next.