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SOE: Fachverband Physik sozio-ökonomischer Systeme

SOE 23: Stochastic Dynamics of Growth Processes in Biological and Social Systems (session accompanying symposium SYGP, joint with DY and BP)

SOE 23.4: Vortrag

Freitag, 4. April 2014, 10:45–11:00, GÖR 226

Selection and drift in expanding bacterial colonies — •Fred Farrell¹, Bartlomiej Waclaw¹, Davide Marenduzzo¹, and Oskar Hallatschek² — ¹School of Physics, University of Edinburgh, Edinburgh, UK — ²Department of Physics, University of California, Berkeley, California, USA

In an expanding population, such as a bacterial colony growing on a surface in the laboratory or in nature, evolution proceeds very differently to in a well-mixed population with a static population size. This is mostly due to the so-called founder effect, where individuals close to the expanding front of the population have a much better chance of passing their genes on to future generations than those deep within the population. Since there are relatively few of these founders, rates of genetic drift are much higher, and the probability that a beneficial mutation will fixate in the population much lower. This is important as it will impact the speed with which such a population adapts to its environment, for example developing antibiotic resistance.

I will present my work using a fairly detailed agent-based biophysical simulation model of an expanding microbial colony to estimate probabilities of fixation of beneficial mutations, and how these depend on the fitness advantage and the properties of the cells, and compare these results to analytical theories of selection in expanding populations.