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Fluctuating selection models and Mcdonald-Kreitman type analyses

journal contribution
posted on 2023-06-08, 16:36 authored by Toni I Gossmann, David Waxman, Adam Eyre-WalkerAdam Eyre-Walker
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.

History

Publication status

  • Published

Journal

PLoS ONE

ISSN

1932-6203

Publisher

Public Library of Science

Issue

1

Volume

9

Article number

e84540

Department affiliated with

  • Evolution, Behaviour and Environment Publications

Full text available

  • Yes

Peer reviewed?

  • Yes

Legacy Posted Date

2014-01-09

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