Evolutionary genetics of sexual dimorphism

理解在行为、形态和生理上形成性别差异的力量，往往是惊人的，是进化生物学的核心难题之一。在一些系统中，我们对形成这些特征的选择力量了解得更多，而在另一些系统中，我们对它们的基因了解得更多。我的建议将重点放在将这些目前不同的项目与三个更具体的主题联系起来。首先，我们将把发育遗传学和基因组学的新工具带到一个我们对性别特异性选择了解很多的群体中。这些工具，结合我们在行为和性状功能方面的专业知识，将使我们能够进行真正的综合研究，将选择与功能、发育、表达和基因组进化联系起来。我们将专注于风湿蝶属，在那里我们已经确定了一个主要的转录因子参与建设二态天线特征在一个物种。我们将对风湿草属的拮抗性状功能进行比较研究，并进行基因敲除，以确定是否相似的遗传因素是这些不同性状的基础。对野生和敲除基因的表达分析将使我们能够确定在物种之间观察到的这些性状差异中涉及的下游基因。在第二个主题中，我们将开始一个新的项目，研究大型和经济上重要的长角甲虫群的显着的两性二态性。在这里，我们将对这些甲虫的一个大部落的物种之间的关系提出一个假设，并研究该群体二态性的进化历史。随后，我们将测量可能解释我们所看到的二态性变化的选择力量。最后，我们将启动一项遗传模式物种秀丽隐杆线虫的研究，这提供了一个被低估的机会，将现有的基因功能和基因组学知识与目前研究不足的性别特异性选择联系起来。利用40个已测序的野生分离株，我们旨在寻找雄性功能进化分歧的迹象及其与雌雄同体的共同进化。下一步将是找到一些驱动这种变异的遗传因素，并研究它们的进化。利用现有的工具，我们还计划使用CRISPR/Cas9基因组编辑技术，将一个合成的性拮抗位点插入到一个具有两个等位基因的进化群体中：一个雄性有害等位基因和一个雌性有害等位基因。在实验进化这些种群40代之后，我们将量化等位基因频率和种群适应性的变化。我们假设在一些人群中，拮抗作用会通过独立的抑制突变被掩盖，而另一些人群可能会保持拮抗作用，甚至积累额外的拮抗等位基因。这个项目将是第一个实证研究，在未来的时间里跟踪性对抗的轨迹。

Understanding the forces that shape the, often spectacular, sexual differences in behaviour, morphology, and physiology is one of the central puzzles of evolutionary biology. In some systems, we know much about the forces of selection shaping these traits, while in other systems we know much about their genetics. My proposal will focus on connecting these currently disparate programs with three more specific themes. In the first, we will bring the new tools of developmental genetics and genomics to a group for which we know much about sex specific selection. These tools, combined with our expertise in behaviour and trait function in the group will allow us to do truly integrative research, linking selection to function, development, expression and genome evolution. We will focus on the genus Rheumatobates, where we have identified a major transcription factor involved in building dimorphic antennal traits in one species. We will undertake a comparative study of antagonistic trait function in the genus Rheumatobates, and conduct knockdowns to determine if similar genetic factors underlie these diverse traits. Expression analyses in wild vs knockdowns will allow us to identify the downstream genes involved in creating the differences in these traits observed among species. In the second theme, we will begin a new program studying the remarkable sexual dimorphism of the large and economically important long-horned beetle group. Here, we will develop a hypothesis for the relationships among species in a large tribe of these beetles, and study the history of the evolution of dimorphism in the group. Subsequently, we will measure the forces of selection that may account for the variation in dimorphism that we see. Finally, we will initiate a study of the genetic model species Caenorhabditis elegans, which provides an underappreciated opportunity to link existing knowledge about gene function and genomics to currently understudied sex specific selection. Using 40 sequenced wild isolates we aim to look for signs of evolutionary divergence in male function and its coevolution with hermaphrodites. The next step will be to find some of the genetic factors that drive this variation and study their evolution. Taking advantage of the available tools we also plan to employ CRISPR/Cas9 genome editing to insert a synthetic and sexually antagonistic locus into an evolving population, with two alleles: a male-detrimental allele and a female-detrimental allele. After experimentally evolving these populations for 40 generations, we will quantify changes in allele frequency and population fitness. We hypothesize that antagonism will be masked in some populations through independent suppressor mutations, while others may maintain antagonism and even accumulate additional antagonistic alleles. This project will be the first empirical study to follow a sexually antagonistic locus in forward time.