Beyond clonal interference: Scrutinizing the complexity of the dynamics of three competing clones

In large adapting clonal species, several beneficial mutations can co-occur, affecting the process of adaptation. Several experimental and theoretical works showed that clonal interference can be an important factor limiting the rate of adaptation. However, models done so far do not embrace the diversity of observed dynamics in experiments, especially non-linear dynamics. We develop here a stochastic model with explicit competitive interactions between clones and describe the complexity of the emerging dynamics of the population, supposing that two mutants enter a resident population in a single copy at different times. These clones can either get fixed, be lost or be maintained in polymorphism, depending on their competitive abilities. We show that frequency-dependent selection can give rise to unexpected dynamics: competitive interactions between clones can foster adaptation by increasing or decreasing both the fixation probability and time of beneficial mutations. We finally estimate the likeliness of frequency-dependent selection and of the different potential final states of the population by assuming prior distributions of the ecological parameters. We show that under our assumptions, non-transitive fitness and non-linear dynamics are likely to play an important role into the adaptation of large clonal populations. Key-words:clonal reinforcement, clonal interference, non-linear dynamics, fixation time, fixation probability, adaptation, cooperation, polymorphism. The authors wish to be identified to the reviewers. ∗Corresponding Author, [email protected] †[email protected] 1 ar X iv :1 60 7. 04 65 6v 1 [ qbi o. PE ] 1 5 Ju l 2 01 6