Figure 2 (image) Institute for Basic Science Share Print E-Mail Caption Example of base substitutions caused by the mutagen MMS (methyl-methan sulfonate) differ between WT (upper panel) and polk DNA repair defective strains (lower panel), T>A changes (indicted in gray) being increased >30 times. Credit IBS Usage Restrictions Please indicate the credit. 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.