Evolutionary genetics of sexual dimorphism

进化生物学的核心难题之一是理解那些塑造了两性在行为、形态和生理上的巨大差异的力量。在某些系统中，我们对塑造这些特征的选择力量了解很多，而在其他系统中，我们对它们的遗传学了解很多。我的建议将集中在连接这些目前不同的程序与三个更具体的主题。 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非常了解性别特异性选择的群体中。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。我们将专注于属Rheoprobates，在那里我们已经确定了一个主要的转录因子参与建设在一个物种的二形触角性状。我们将进行一项拮抗性状功能的比较研究，在属Rhetorobates，并进行敲除，以确定是否相似的遗传因素，这些不同的性状。在野生型与敲除型中的表达分析将使我们能够识别参与创造物种间观察到的这些性状差异的下游基因。 在第二个主题中，我们将开始一个新的项目，研究大型的、经济上重要的长角甲虫群体的显著的两性异形。在这里，我们将发展一个假设，在这些甲虫的一个大部落的物种之间的关系，并研究在组的二型性的进化历史。随后，我们将测量可能解释我们所看到的二型性变化的选择力。 最后，我们将启动遗传模式物种秀丽隐杆线虫的研究，这提供了一个未得到充分重视的机会，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。使用40个测序的野生菌株，我们的目标是寻找男性功能的进化分歧的迹象，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基因组编辑将合成的性拮抗基因座插入到进化的种群中，该基因座具有两个等位基因：一个男性有害等位基因和一个女性有害等位基因。经过40代的实验进化，我们将量化等位基因频率和群体适应度的变化。我们假设，在某些人群中，拮抗作用将通过独立的抑制基因突变被掩盖，而另一些人可能保持拮抗作用，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，以遵循性拮抗位点在未来的时间。

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.