Chromatin (image) Brown University Caption Cells control harmful transposons in DNA by wrapping them tightly around nucleosomes and packing them into chromatin fibers. The ability to maintain control of harmful transposons diminishes as cells age. Credit: Darryl Leja/National Human Genome Research Institute Credit Darryl Leja/National Human Genome Research Institute Usage Restrictions With credit 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.