Mutation-accumulation Experiment (IMAGE) Washington University in St. Louis Caption In the mutation accumulation experiment, amoebae were allowed to reproduce until they formed a visible plaque, and then one was picked at random and carried to a new plate where it was allowed to reproduce and so on. Because the amoebae were picked at random and never allowed to form fruiting bodies, natural selection wasn’t removing harmful mutations; instead they were "fixed," or became a permanent part of a line's genome. The experiment showed that mutations that create cheaters don't happen all that often. Credit Strassmann/Queller Usage Restrictions please credit 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.