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Theor Popul Biol. 2013 May;85:86-102. doi: 10.1016/j.tpb.2013.01.005. Epub 2013 Jan 18.

Fluctuations in fitness distributions and the effects of weak linked selection on sequence evolution.

Author information

1
Department of Organismic and Evolutionary Biology, Department of Physics, and FAS Center for Systems Biology, Harvard University, United States.

Abstract

Evolutionary dynamics and patterns of molecular evolution are strongly influenced by selection on linked regions of the genome, but our quantitative understanding of these effects remains incomplete. Recent work has focused on predicting the distribution of fitness within an evolving population, and this forms the basis for several methods that leverage the fitness distribution to predict the patterns of genetic diversity when selection is strong. However, in weakly selected populations random fluctuations due to genetic drift are more severe, and neither the distribution of fitness nor the sequence diversity within the population are well understood. Here, we briefly review the motivations behind the fitness-distribution picture, and summarize the general approaches that have been used to analyze this distribution in the strong-selection regime. We then extend these approaches to the case of weak selection, by outlining a perturbative treatment of selection at a large number of linked sites. This allows us to quantify the stochastic behavior of the fitness distribution and yields exact analytical predictions for the sequence diversity and substitution rate in the limit that selection is weak.

PMID:
23337315
DOI:
10.1016/j.tpb.2013.01.005
[Indexed for MEDLINE]

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