Fluctuating selection models and Mcdonald-Kreitman type analyses

Gossmann, Toni I, Waxman, David and Eyre-Walker, Adam (2014) Fluctuating selection models and Mcdonald-Kreitman type analyses. PLoS ONE, 9 (1). e84540. ISSN 1932-6203

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Abstract

It is likely that the strength of selection acting upon a mutation varies through time due to changes in the environment. However, most population genetic theory assumes that the strength of selection remains constant. Here we investigate the consequences of fluctuating selection pressures on the quantification of adaptive evolution using McDonald-Kreitman (MK) style approaches. In agreement with previous work, we show that fluctuating selection can generate evidence of adaptive evolution even when the expected strength of selection on a mutation is zero. However, we also find that the mutations, which contribute to both polymorphism and divergence tend, on average, to be positively selected during their lifetime, under fluctuating selection models. This is because mutations that fluctuate, by chance, to positive selected values, tend to reach higher frequencies in the population than those that fluctuate towards negative values. Hence the evidence of positive adaptive evolution detected under a fluctuating selection model by MK type approaches is genuine since fixed mutations tend to be advantageous on average during their lifetime. Never-the-less we show that methods tend to underestimate the rate of adaptive evolution when selection fluctuates.

Item Type: Article
Schools and Departments: School of Life Sciences > Evolution, Behaviour and Environment
Subjects: Q Science > QH Natural history > QH0301 Biology > QH0359 Evolution
Q Science > QH Natural history > QH0301 Biology > QH0426 Genetics > QH0447 Genes. Alleles. Genome
Q Science > QH Natural history > QH0301 Biology > QH0426 Genetics > QH0460 Mutations
Depositing User: Adam Eyre-Walker
Date Deposited: 09 Jan 2014 14:44
Last Modified: 07 Mar 2017 05:09
URI: http://sro.sussex.ac.uk/id/eprint/47337

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