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BP: Fachverband Biologische Physik
BP 32: Evolutionary Game Theory II (joint SOE/BP/DY)
BP 32.3: Talk
Tuesday, March 17, 2015, 14:30–14:45, MA 001
Non-selective evolution of growing populations — •Karl Wienand1, Matthias Lechner1, Felix Becker2, Heinrich Jung2, and Erwin Frey1 — 1Arnold Sommerfeld Center for Theoretical Physics, Ludwig-Maximilians Universität, Munich, Germany — 2Biozentrum, Ludwig-Maximilians Universität, Munich, Germany
Evolution results from the interplay between directed selection and non-selective effects. Most theoretical analyses of non-selective evolution rely on constant population sizes and result in some trait taking over the entire population. However, bacterial populations both in nature and in the laboratory are often observed during their exponential growth. In this work we show that, during growth, populations "freeze" to a random steady state composition. To show this, we employed theoretical models based on Pólya urns and performed experiments on two Pseudomonas putida strains in non-selective conditions. We found excellent agreement between experiments and theory. We were also able to elucidate the importance of initial conditions on the steady state distribution on population compositions. In particular, the initial size of the populations can tune the relative importance of initial assortment and growth as noise sources for the final distribution.