Chenoweth Stephen F, Appleton Nicholas C, Allen Scott L, Rundle Howard D
School of Biological Sciences, University of Queensland, St. Lucia, Brisbane 4072, Australia.
School of Biological Sciences, University of Queensland, St. Lucia, Brisbane 4072, Australia.
Curr Biol. 2015 Jul 20;25(14):1860-6. doi: 10.1016/j.cub.2015.05.034. Epub 2015 Jun 25.
Sexual selection is widely appreciated for generating remarkable phenotypic diversity, but its contribution to adaptation and the purging of deleterious mutations is unresolved. To provide insight into the impact of sexual selection on naturally segregating polymorphisms across the genome, we previously evolved 12 populations of Drosophila serrata in a novel environment employing a factorial manipulation of the opportunities for natural and sexual selection. Here, we genotype more than 1,400 SNPs in the evolved populations and reveal that sexual selection affected many of the same genomic regions as natural selection, aligning with it as often as opposing it. Intriguingly, more than half of the 80 SNPs showing treatment effects revealed an interaction between natural and sexual selection. For these SNPs, while sexual selection alone often caused a change in allele frequency in the same direction as natural selection alone, when natural and sexual selection occurred together, changes in allele frequency were greatly reduced or even reversed. This suggests an antagonism between natural and sexual selection arising from male-induced harm to females. Behavioral experiments showed that males preferentially courted and mated with high-fitness females, and that the harm associated with this increased male attention eliminated the female fitness advantage. During our experiment, females carrying otherwise adaptive alleles may therefore have disproportionally suffered male-induced harm due to their increased sexual attractiveness. These results suggest that a class of otherwise adaptive mutations may not contribute to adaptation when mating systems involve sexual conflict and male mate preferences.
性选择因产生显著的表型多样性而广为人知，但其对适应性和有害突变清除的贡献仍未得到解决。为了深入了解性选择对全基因组自然分离多态性的影响，我们之前在一个新环境中对12个锯缘果蝇种群进行了进化实验，采用了对自然选择和性选择机会的析因操作。在这里，我们对进化后的种群中的1400多个单核苷酸多态性（SNP）进行了基因分型，发现性选择影响的许多基因组区域与自然选择相同，与其一致的情况和与其相反的情况一样常见。有趣的是，在显示出处理效应的80个SNP中，超过一半揭示了自然选择和性选择之间的相互作用。对于这些SNP，虽然单独的性选择往往会导致等位基因频率朝着与单独的自然选择相同的方向变化，但当自然选择和性选择同时发生时，等位基因频率的变化会大大减少甚至逆转。这表明自然选择和性选择之间存在一种由雄性对雌性造成的伤害所引起的拮抗作用。行为实验表明，雄性优先追求高适应性的雌性并与其交配，而这种增加的雄性关注所带来的伤害消除了雌性的适应性优势。因此，在我们的实验过程中，携带其他适应性等位基因的雌性可能由于其增加的性吸引力而不成比例地遭受雄性造成的伤害。这些结果表明，当交配系统涉及性冲突和雄性配偶偏好时，一类其他适应性的突变可能不会对适应性做出贡献。
