¹Evolution and Behaviour Research Group, School of Biology, University of Newcastle upon Tyne, Newcastle-upon-Tyne, UK

Correspondence: Professor M Petrie, Current address. Evolutionary Biology Group, SCMS, William Leech Building, Newcastle University, Newcastle-upon-Tyne, NE1 4HH, UK. E-mail: marion.petrie@ncl.ac.uk

Received 25 August 2006; Revised 30 September 2006; Accepted 17 October 2006; Published online 22 November 2006.

Abstract

Here we show that sexual selection can have an effect on the rate of mutation. We simulated the fate of a genetic modifier of the mutation rate in a sexual population with and without sexual selection (modelled using a female choice mechanism). Female choice for 'good genes' should reduce variability among male subjects, leaving insufficient differences to maintain female preferences. However, female choice can actually increase genetic variability by supporting a higher mutation rate in sexually selected traits. Increasing the mutation rate will be selected against because of the resulting decline in mean fitness. However, it also increases the probability of rare beneficial mutations arising, and mating skew caused by female preferences for male subjects carrying those beneficials with few deleterious mutations ('good genes') can lead to a mutation rate above that expected under natural selection. A choice of two male subjects was sufficient for there to be a twofold increase in the mutation rate as opposed to a decrease found under random mating.