Ellen Baake: Modelling and simulating Lenski’s long-term evolution experiment

  • Date: Apr 29, 2019
  • Time: 10:00 AM - 11:00 AM (Local Time Germany)
  • Speaker: Ellen Baake from Bielefeld University, Germany
  • For more information on the speaker, please visit https://www.techfak.uni-bielefeld.de/ags/bm/people/ellen.htm
  • Location: MPI Plön
  • Room: Lecture hall
  • Host: Julien Dutheil


We revisit the model by Wiser, Ribeck, and Lenski (Science 342 (2013), 1364–1367), which describes how the mean fitness increases over time due to beneficial mutations in Lenski’s long-term evolution experiment. We develop the model further both conceptually and mathematically.
Conceptually, we describe the experiment with the help of a Cannings model with mutation and selection, where the latter includes diminishing returns epistasis. The analysis sheds light on the growth dynamics within every single day and reveals a runtime effect, that is, the shortening of the daily growth period with increasing fitness; and it allows to clarify the contribution of epistasis to the mean fitness curve. Mathematically, we explain rigorous results in terms of a law of large numbers (in the limit of infinite population size and for a certain asymptotic parameter regime), and present approximations based on heuristics and supported by simulations for finite populations.

This is joint work with Adrián González Casanova, Sebastian Probst, and Anton Wakolbinger.

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