School of Biological Sciences, The University of Queensland, St Lucia, Queensland 4072, Australia.
Evolution. 2011 Oct;65(10):2816-29. doi: 10.1111/j.1558-5646.2011.01346.x. Epub 2011 Jun 28.
Mutation load is a key parameter in evolutionary theories, but relatively little empirical information exists on the mutation load of populations, or the elimination of this load through selection. We manipulated the opportunity for sexual selection within a mutation accumulation divergence experiment to determine how sexual selection on males affected the accumulation of mutations contributing to sexual and nonsexual fitness. Sexual selection prevented the accumulation of mutations affecting male mating success, the target trait, as well as reducing mutation load on productivity, a nonsexual fitness component. Mutational correlations between mating success and productivity (estimated in the absence of sexual selection) were positive. Sexual selection significantly reduced these fitness component correlations. Male mating success significantly diverged between sexual selection treatments, consistent with the fixation of genetic differences. However, the rank of the treatments was not consistent across assays, indicating that the mutational effects on mating success were conditional on biotic and abiotic context. Our experiment suggests that greater insight into the genetic targets of natural and sexual selection can be gained by focusing on mutational rather than standing genetic variation, and on the behavior of trait variances rather than means.
突变负荷是进化理论中的一个关键参数，但关于种群的突变负荷或通过选择消除这种负荷的相对较少的经验信息。我们在一个突变积累分化实验中操纵了性选择的机会，以确定雄性的性选择如何影响导致性和非性适合度的突变的积累。性选择阻止了影响雄性交配成功率的突变的积累，而交配成功率是目标性状，同时也降低了非性适合度成分生产力的突变负荷。在没有性选择的情况下，交配成功率和生产力之间的突变相关性是正相关的。性选择显著降低了这些适合度成分的相关性。在性选择处理之间，雄性交配成功率显著分化，这与遗传差异的固定一致。然而，处理的等级在不同的测定中并不一致，这表明对交配成功率的突变影响取决于生物和非生物的环境。我们的实验表明，通过关注突变而不是静态遗传变异，以及关注性状方差而不是均值，可以更深入地了解自然和性选择的遗传目标。
