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

进化生物学家研究地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。虽然男性和女性在生殖方面存在明显的差异，但他们在其他特征上也不同。这些额外的差异令人费解，因为性别几乎共享所有的基因，这表明其中一些基因的不同形式必须在男性和女性身上找到。这些差异应该会在女性偏爱的基因和男性偏爱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。这项研究将研究特里尼迪亚孔雀鱼的雄性和雌性如何对新环境做出反应。它将利用一项为期八年的进化实验研究，询问性别之间的冲突是从一开始就可见，还是只有在两性都适应了新环境的主要特征后才出现。作为该项目的一部分，将向公众和K-12学生进行宣传，来自代表性不足群体的本科生将参与这项研究。自然选择对表型变异的强度和方向在种群内的所有个体中并不相等。特别是，当选择在男性和女性之间产生对立行为时，性别之间的遗传相关性可能会产生局灶内性冲突。最近的研究揭示了性别对抗选择可能产生的进化约束，但它在一般适应过程中的作用尚不清楚。理论表明，在适应新环境的人群中，局灶内性冲突将是最小的，只有当人群接近适应高峰时才会出现。本研究将通过回答以下问题来解决局灶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从一开始就影响适应过程，还是在特征值接近最佳时对后来的适应过程有更大的影响？(2)性别之间的对立关系是随着时间的推移而变化，允许还是限制了性二态的演变？该项目将进化的实验研究与大规模标记-重新捕获项目和下一代测序的统计工具相结合。自实验开始以来，这些实验种群中几乎每一只孔雀鱼都可以获得遗传和表型样本。这些数据提供了估计适合度、配偶选择、特征遗传力和性别之间的遗传协方差的机会。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的遗传学问题。

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.