The Graph Illustrates How Radiation Alters the Genome (image) University of Bonn Share Print E-Mail Caption A 'multisite de novo mutation' (MSDN) occurs when two or more defects occur adjacently in the DNA strands of 20 base pairs. Credit © Jean-Tori Pantel Usage Restrictions This image may be used with the press release. Share Print E-Mail 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.