VW Research Group Experimental Ecology and Evolution

    Microorganisms are well known to readily enter into synergistic interactions with both other micro- or macroorganisms. The molecular prerequisites and selective conditions that favour/ hamper the evolution of such cooperative interactions, however, remain poorly understood.

   Our main goal is to answer the question: Why do organisms cooperate with each other? For this, we use microorganisms as an experimentally tractable model. By rigorously and systematically studying the physiological and genetic causes as well as the ecological and evolutionary consequences of a cooperative lifestyle, we aim to contribute to the development of a solid, empirically-based framework that allows to mechanistically predict the evolution of cooperative behaviours within microbial communities.

   We address this fascinating research question by combining the methodological power of evolution experiments with recent advances in the field of molecular microbiology and synthetic systems biology. First, specific ecological interactions between different microorganisms are synthetically engineered. The rationale of this design is based on a priori knowledge on the essential features of the focal interaction and its genetic implementation is guided by computational approaches. Second, theoretical models are being developed that provide testable hypotheses, which are then experimentally verified by exposing precisely defined microbial consortia to certain environmental conditions or selection pressures. These experiments are either performed on ecological time-scales, to monitor fitness-related shifts in the frequency distributions of the interacting populations, or in long-term evolution experiments, during which new genotypes arise by mutation and selection. Finally, post-hoc analyses are performed to study the underlying processes on a phenotypic, a physiological, and a genetic level. This laboratory-based approach is complemented by the study of natural microbial populations, in which we verify the general applicability of our findings.