A recently published study offers new clues about the evolution of the immune system in European populations of the plant Arabidopsis thaliana and the underlying genetic mechanisms associated with immunity. The study, published in the journal PLOS Genetics, is signed by Rubén Alcázar, Ramón y Cajal researcher in the Department of Natural Products, Plant Biology and Soil Science of the Faculty of Pharmacy at the University of Barcelona (UB), together with researchers from the Max Plack Institute for Plant Breeding Research and the Max Planck Institute for Developmental Biology, in Germany.