Sexual selection, conflict and isolation: experimental insight into the population genetic consequences of mate competition and the origin of species

性选择、冲突和隔离：对配偶竞争和物种起源的群体遗传后果的实验洞察

• 批准号: RGPIN-2021-03358
• 负责人: Rundle, Howard
• 金额: $ 5.68万
• 依托单位: University of Ottawa
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=745588
• 关键词: Sexual; selection; conflict; isolation; experimental

In most sexually reproducing species, males compete for access to mates and/or to fertilize their gametes. Such competition is persistent, widespread, and often intense, and it generates the variation in reproductive success that causes sexual selection. Mate competition is also a key reason why selection differs between males and females, and the resulting sexual conflict can lead to the evolution of traits that benefit males but harm females as a by-product. The evolution of extravagant sexual displays, like the peacock's tail, and exaggerated weapons of sexual rivalry, like a buck's antlers, are well-understood consequences of mate competition; such traits evolve because they increase a male's sexual fitness relative to other males. However, through its effects on sexual selection, sexual conflict, and patterns of mating, mate competition has other evolutionary consequences that are poorly understood, yet arguably fundamental. My research seeks a more comprehensive understanding of these, focussing on the evolutionary consequences of mate competition for: i) nonsexual fitness, via its effects on adaptation to novel environments and the purging of harmful mutations; ii) sex-biased gene expression, which underlies the extensive sexual dimorphism and that constitutes a major component of biological diversity; and iii) sexual isolation, a barrier to gene flow between populations that is important to the origin of new species. Working with fruit flies (Drosophila) and other insects, in both the lab and the field, we use a combination of behavioural and fitness assays, and we rely heavily on the power of experimental evolution, enabling us to compare how the evolutionary process unfolds in replicate populations under different mate competition regimes. We give particular attention to the ecology of the mating environment, studying how it alters the evolutionary consequences of mate competition and whether the highly unusual lab environment of Drosophila studies -a model system for work on this topic- may have biased our perspective. We provide manipulative tests of the underlying mechanisms by which ecology alters mate competition and the effects this has on adaptation and purging. We also quantify how sex-biased gene expression evolves in response to manipulations of mate competition and the environment in which this occurs, and how mate competition and its ecology affect speciation. Over 160 years ago, Darwin suggested that, because sexual selection favours the healthiest and most vigorous males, the broader evolutionary consequence of mate competition is increased adaptation. This, it turns out, was too simplistic; mate competition can have complex and environment-dependent effects with a variety of population genetic consequence that include, but are not limited to, adaptation. This work has broad implications for our understanding of fundamental evolutionary processes and how ecology shapes them.

在大多数有性繁殖的物种中，雄性会竞争交配和/或使配子受精。这种竞争是持续的、广泛的，而且往往很激烈，它会产生繁殖成功率的变化，从而导致性选择。配偶竞争也是雄性和雌性之间选择不同的一个关键原因，由此产生的性冲突可能导致对雄性有利但对雌性不利的副产品特征的进化。孔雀尾巴等奢侈的性展示，以及雄鹿角等夸张的性竞争武器的演变，都是众所周知的配偶竞争的后果。这些特征的进化是因为它们提高了雄性相对于其他雄性的性适应性。然而，通过对性选择、性冲突和交配模式的影响，交配竞争还产生了其他一些我们知之甚少但可以说是根本性的进化后果。我的研究寻求对这些问题有更全面的了解，重点关注配偶竞争的进化后果：i）非性适应性，通过其对适应新环境和清除有害突变的影响； ii) 性别偏向的基因表达，它是广泛的性别二态性的基础，也是生物多样性的主要组成部分； iii) 性隔离，这是种群之间基因流动的障碍，这对新物种的起源很重要。 在实验室和野外，我们以果蝇（果蝇）和其他昆虫为对象，结合使用行为和适应性测定，并且在很大程度上依赖实验进化的力量，使我们能够比较进化过程如何在不同环境中展开。在不同的交配竞争机制下复制种群。我们特别关注交配环境的生态学，研究它如何改变交配竞争的进化后果，以及果蝇研究的极不寻常的实验室环境（该主题工作的模型系统）是否可能使我们的观点产生偏差。我们对生态改变配偶竞争的潜在机制及其对适应和净化的影响进行了操作性测试。我们还量化了性别偏见基因表达如何响应配偶竞争的操纵和发生这种情况的环境而进化，以及配偶竞争及其生态如何影响物种形成。 160 多年前，达尔文提出，由于性选择有利于最健康、最有活力的雄性，因此交配竞争更广泛的进化结果是适应性的增强。事实证明，这个想法过于简单化了。配偶竞争可能会产生复杂且依赖于环境的影响，并产生多种群体遗传后果，包括但不限于适应。这项工作对于我们理解基本进化过程以及生态如何塑造它们具有广泛的意义。