Phenotypic sexual dimorphism is associated with genomic signatures of resolved sexual conflict

Intra-locus sexual conflict, where an allele benefits one sex at the expense of the other, has an important role in shaping genetic diversity of populations through balancing selection. However, the potential for mating systems to exert balancing selection through sexual conflict on the genome remains unclear. Furthermore, the nature and potential for resolution of sexual conflict across the genome has been hotly debated. To address this, we analysed de novo transcriptomes from six avian species, chosen to reflect the full range of sexual dimorphism and mating systems. Our analyses combine expression and population genomic statistics across reproductive and somatic tissue, with measures of sperm competition and promiscuity. Our results reveal that balancing selection is weakest in the gonad, consistent with the resolution of sexual conflict and evolutionary theory that phenotypic sex differences are associated with lower levels of ongoing conflict. We also demonstrate a clear link betwe...基因座内性冲突（Intra-locus sexual conflict）指某一等位基因以牺牲另一性别为代价使其一性获益，该现象通过平衡选择在塑造种群遗传多样性方面发挥着关键作用。然而，交配系统通过性冲突对基因组施加平衡选择的潜在机制仍不明朗。此外，全基因组范围内性冲突的本质及其解决潜力一直是学界热议的话题。为解答这一科学问题，我们对6种鸟类的从头转录组（de novo transcriptomes）展开分析，所选物种覆盖了性二态性（sexual dimorphism）与交配系统的全部谱系范围。本研究整合生殖组织与体细胞组织的表达及群体基因组统计量，并结合精子竞争（sperm competition）与多配性相关指标开展分析。结果显示，性腺中的平衡选择作用最弱，这与性冲突的缓解及进化理论相契合——表型性别差异与更低水平的持续性冲突相关。我们还证实了……之间的明确关联。