Annah S. Rolig, University of Oregon (IMAGE) University of Oregon Caption Annah S. Rolig, a postdoctoral researcher at the University of Oregon, led a project that focused on the individual contributions of bacterial species in the guts of germ-free zebrafish. Her team found that an abundance of a species is not what drives immune response. Species in very low abundance can be the important regulators. Credit University of Oregon 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.