The battle of the sexes over seed size: support for both kinship genomic imprinting and interlocus contest evolution

utcrossing creates a venue for parental conflict. When one sex provides parental care to offspring fertilized by several partners, the nonproviding sex is under selection to maximally exploit the caring sex. The caring sex may counteradapt, and a coevolutionary arms race ensues. Genetic models of this conflict include the kinship theory of genomic imprinting (parent-of-origin-specific expression of maternal-care effectors) and interlocus conflict evolution (interaction between male selfish signals and female abatement). Predictions were tested by measuring the sizes of seeds produced by within-population crosses (diallel design) and between-population crosses in outcrossing and selfing populations of Arabidopsis lyrata. Within-population diallel crosses revealed substantial maternal variance in seed size in most populations. The comparison of between- and within-population crosses showed that seeds were larger when pollen came from another outcrossing population than when pollen came fr...异交（outcrossing）创设了亲本冲突的发生情境。当某一性别为多个配偶受精产生的后代提供亲本抚育时，未提供抚育的性别会受到自然选择的作用，以最大化利用提供抚育的性别。提供抚育的性别可能产生反适应，由此引发协同进化军备竞赛。此类冲突的遗传模型包括基因组印记（genomic imprinting）的亲缘关系理论（即母本抚育效应因子的亲本起源特异性表达），以及基因座间冲突进化理论（雄性自私信号与雌性抑制响应的相互作用）。研究通过测定lyrata拟南芥（Arabidopsis lyrata）异交与自交种群的种群内杂交（双列杂交设计，diallel design）和种群间杂交所产生的种子大小，对上述理论预测进行了验证。种群内双列杂交实验显示，多数种群的种子大小存在显著的母本方差。种群间与种群内杂交的对比结果表明，当花粉来自另一异交种群时，所结种子的尺寸大于花粉来自同种群时的……