Mu for Mutation Rate (IMAGE) University of Pennsylvania School of Medicine Caption This is Mu, the Greek symbol commonly used to symbolize mutation rate. Credit Image courtesy of Stacie Bumgarner (2016) Usage Restrictions None License Licensed content 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.