Chromosomes (image) Salk Institute Caption Each time a cell divides, the protective "caps" at the tip of chromosomes (red and green dots) erode a little bit further. As telomeres wear down, their DNA undergoes massive changes in the way it is packaged. These changes likely trigger what we call "aging." Credit Image: Courtesy of Dr. Jan Karlseder, Salk Institute for Biological Studies Usage Restrictions News media reproduction to illustrate this story permitted with proper attribution as provided above. For one time use only. Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.