Dissertation Research: Conflict and the Evolution of Dimorphism in the Trinidadian Guppy

进化生物学家研究我们星球上生命的多样性以及它是如何产生的。一个特别重要的问题是性别之间的多样性。虽然雄性和雌性在与生殖有关的明显方式上有所不同，但它们在其他特征上也有所不同。这些额外的差异令人困惑，因为两性几乎拥有所有的基因，这表明其中一些基因的不同形式必须在男性和女性中找到。这些差异应该会在女性偏好的基因和男性偏好的基因之间产生冲突。这项研究正在寻找这种冲突的证据，更重要的是，这种冲突是否是两性不可避免的特征。这项研究将研究特立尼达孔雀鱼的雄性和雌性如何进化以应对新的环境。它将利用一项为期八年的进化实验研究来询问性别之间的冲突是否从一开始就显而易见，或者是否只有在两性都适应了新环境的主要特征后才会出现。作为该项目的一部分，将与公众和K-12学生进行接触，来自代表性不足群体的本科生将参与研究。 自然选择对表型变异的作用强度和方向在种群内的所有个体之间是不相等的。特别是，当选择在男性和女性之间起对抗作用时，性别之间的遗传相关性会产生基因座内的性冲突。 最近的工作揭示了进化的限制，性拮抗选择可以产生，但它在适应的一般过程中的作用仍然不清楚。理论表明，在适应新环境的种群中，基因座内的性冲突将是最小的，只有当种群接近其适应性高峰时才会出现。本研究将通过回答以下问题来探讨基因座内性冲突在适应过程中的作用：（1）性对抗选择和由此产生的性冲突是否从一开始就影响适应过程，或者当性状值接近最佳值时，它是否会产生更大的影响？(2)两性之间的对抗关系是否随着时间的推移而改变，从而允许或限制了两性异形的进化？该项目将进化的实验研究与大规模标记重捕获项目和下一代测序的统计工具相结合。遗传和表型样本可用于这些实验种群中的几乎每一个孔雀鱼，可以追溯到实验开始。这些数据提供了机会，以估计健身，配偶选择，性状遗传力，和性别之间的遗传协方差。使用这个系统和这些方法，研究人员将以一种以前不可能的方式回答关于适应遗传学的问题。

Evolutionary biologists study the diversity of life on our planet and how it has been generated. One particularly important question is the diversity between sexes. While males and females are different in obvious ways related to reproduction, they also differ in other features. These additional differences are puzzling because the sexes share nearly all of their genes, and this suggests that different forms of some of those genes must be found in males and females. These differences should create a conflict between genes favored in females and genes favored in males. This research is looking for evidence of that conflict and, more importantly, whether that conflict is an unavoidable feature of having two sexes. The research will examine how males and females of the Trinidadian guppy evolve in response to a new environment. It will take advantage of an eight-year experimental study of evolution to ask if the conflict between sexes has been visible from the start or whether it emerges only after both sexes have adapted to the major features of a novel environment. Outreach to the public and K-12 students will occur as part of this project, and undergraduates from underrepresented groups will be involved in the research.  The strength and direction of natural selection on phenotypic variation is not equal among all individuals within a population. In particular, genetic correlations between the sexes can produce intralocus sexual conflicts when selection acts antagonistically between males and females.  Recent work has shed light on the evolutionary constraint that sexually antagonistic selection can produce, but its role in the general process of adaptation remains unclear. Theory suggests that intralocus sexual conflict will be minimal in a population adapting to a novel environment and will emerge only when populations approach their adaptive peaks. This research will address the role of intralocus sexual conflict on the adaptive process by answering these questions: (1) Does sexually antagonistic selection and the resulting sexual conflict influence the adaptive process from the start or does it have more of an influence later when trait values approach their optimum? (2) Does the antagonistic relationship between the sexes change over time allowing for or limiting the evolution of sexual dimorphism? This project integrates the experimental study of evolution with the statistical tools of a large-scale mark-recapture project and next-generation sequencing. Genetic and phenotypic samples are available for nearly every guppy within these experimental populations dating to the start of the experiment. These data provide the opportunity to estimate fitness, mate choice, trait heritability, and the genetic covariance between the sexes. Using this system and these methods, the researchers will answer questions on the genetics of adaptation in a manner not previously possible.