A Small Difference Led to a Big Discovery (image) Washington University in St. Louis Share Print E-Mail Caption The two strains of bacteria hitching a ride on a D. Discoideum clone belonged to the same species but they plated out differently. One formed colonies with smooth edges and the other formed colonies with bumpy edges. This observation eventually led to the discovery that one was edible and the other produced defensive chemicals. The D. discoideum travels well-equipped. Credit Debra Brock Usage Restrictions please 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.