Sexual selection, body mass, and molecular evolution interact to predict diversification in birds

Sexual selection is a powerful agent of evolution, driving microevolutionary changes in the genome and macroevolutionary rates of lineage diversification. The mechanisms by which sexual selection might influence macroevolution remain poorly understood. For example, sexual selection might drive positive selection for key adaptations that facilitate diversification. Furthermore, sexual selection might be a general driver of molecular evolutionary rate. We lay out some of the potential mechanisms that create a link between sexual selection and diversification, based on causal effects on other life-history traits such as body mass and the rate of molecular evolution. Birds are ideally suited for testing the importance of these relationships because of their diverse reproductive systems and the multiple evolutionary radiations that have produced their astounding modern diversity. We show that sexual selection (measured as the degree of polygyny) interacts with the rate of molecular evolution...性选择（Sexual selection）是一种强效的进化驱动力，可驱动基因组层面的微进化变化，并影响类群分化的宏观进化速率。目前学界对性选择调控宏观进化的具体机制仍知之甚少。例如，性选择可能会推动助力类群分化的关键适应性性状经历正向选择。此外，性选择或许是分子进化速率的普遍驱动力。本研究基于性选择对体重、分子进化速率等生活史性状的因果效应，梳理了若干可建立性选择与类群分化之间关联的潜在机制。鸟类拥有多样的生殖系统，且经历了多次进化辐射事件，造就了如今惊人的物种多样性，因此是验证上述关联重要性的理想研究体系。本研究证实，以一雄多雌程度为量化指标的性选择与分子进化速率存在交互作用。