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Item Type: | Article |
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Title: | Distribution of the fittest individuals and the rate of Muller's ratchet in a model with overlapping generations |
Creators Name: | Metzger, J.J. and Eule, S. |
Abstract: | Muller's ratchet is a paradigmatic model for the accumulation of deleterious mutations in a population of finite size. A click of the ratchet occurs when all individuals with the least number of deleterious mutations are lost irreversibly due to a stochastic fluctuation. In spite of the simplicity of the model, a quantitative understanding of the process remains an open challenge. In contrast to previous works, we here study a Moran model of the ratchet with overlapping generations. Employing an approximation which describes the fittest individuals as one class and the rest as a second class, we obtain closed analytical expressions of the ratchet rate in the rare clicking regime. As a click in this regime is caused by a rare, large fluctuation from a metastable state, we do not resort to a diffusion approximation but apply an approximation scheme which is especially well suited to describe extinction events from metastable states. This method also allows for a derivation of expressions for the quasi-stationary distribution of the fittest class. Additionally, we confirm numerically that the formulation with overlapping generations leads to the same results as the diffusion approximation and the corresponding Wright-Fisher model with non-overlapping generations. |
Keywords: | Computational Biology, Genetic Fitness, Genetic Models, Genetic Selection, Molecular Evolution, Mutation |
Source: | PLoS Computational Biology |
ISSN: | 1553-734X |
Publisher: | Public Library of Science |
Volume: | 9 |
Number: | 11 |
Page Range: | e1003303 |
Date: | November 2013 |
Official Publication: | https://doi.org/10.1371/journal.pcbi.1003303 |
PubMed: | View item in PubMed |
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