Sexual conflict and the gender load: correlated evolution between population fitness and sexual dimorphism in seed beetles
Sexual conflict and the gender load: correlated evolution between population fitness and sexual dimorphism in seed beetles
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DOI：
10.1098/rspb.2009.2026
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发表时间：
2010-05-07
影响因子：
4.7
通讯作者：
Tuda, Midori
中科院分区：
文献类型：
--
作者：
Arnqvist, Goran;Tuda, Midori
尽管雄性和雌性拥有大部分相同的基因组，但两种性别的选择通常是不同的。理论上，性对抗位点会在人群中造成性别负荷，因为对一种性别的特定性状的性别特异性选择会损害另一种性别的相同性状的适应性进化。然而，目前尚不清楚这种位点内性冲突（ISC）是否代表一种短暂的进化状态，其中冲突通过性二态性（SD）的进化迅速解决，或者它是否是一种更长期的适应障碍。在其他条件相同的情况下，ISC 应该表现为群体适应性和两性特征 SD 之间的相关进化。然而，这一预测的比较测试存在问题并且不可行。在这里，我们通过比较不同实验室种子甲虫种群的适应性和 SD 来评估 ISC 的影响，这些种子甲虫应该很好地适应共享环境。我们表明，幼年发育期的 SD 是该模型系统中具有性对抗选择历史的关键生活史特征，与适应性呈正相关。这种效应是由于种群适应性和发育时间之间的相关演化而导致的，这种演化对于女性来说是正向的，但对于男性来说是负向的。放松两性之间的遗传联系显然使两性能够接近各自独特的适应峰值。
Although males and females share much of the same genome, selection is often distinct in the two sexes. Sexually antagonistic loci will in theory cause a gender load in populations, because sex-specific selection on a given trait in one sex will compromise the adaptive evolution of the same trait in the other sex. However, it is currently not clear whether such intralocus sexual conflict (ISC) represents a transient evolutionary state, where conflict is rapidly resolved by the evolution of sexual dimorphism (SD), or whether it is a more chronic impediment to adaptation. All else being equal, ISC should manifest itself as correlated evolution between population fitness and SD in traits expressed in both sexes. However, comparative tests of this prediction are problematic and have been unfeasible. Here, we assess the effects of ISC by comparing fitness and SD across distinct laboratory populations of seed beetles that should be well adapted to a shared environment. We show that SD in juvenile development time, a key life-history trait with a history of sexually antagonistic selection in this model system, is positively related to fitness. This effect is due to a correlated evolution between population fitness and development time that is positive in females but negative in males. Loosening the genetic bind between the sexes has evidently allowed the sexes to approach their distinct adaptive peaks.