Collaborative Research: The Evolution of Extreme Trait Size

从大力神甲虫的角到麋鹿的鹿角，为获得繁殖机会而进行的激烈选择推动了极端动物武器的进化。极端武器通常比身体其他部位进化得更快，而且它们在不同物种之间往往比身体其他部位更多样化。然而，很少有研究直接衡量自然人群中对武器的选择，对导致武器快速进化的基因和发展路径几乎一无所知。这个项目利用了犀牛甲虫的种群，犀牛甲虫的相对大小在武器的相对大小上有很大差异，犀牛甲虫是从雄性犀牛的头上伸出的“干草叉”角。通过严格研究甲虫在不同种群中的行为，研究人员将测试选择强度的局部差异是否推动了武器大小最近的快速进化变化。研究这些甲虫种群中相关基因的分布，以及识别与这些极端特征相关的额外基因及其在基因组中的位置，将进一步加深我们对武器进化的遗传基础的理解，建立在这些研究人员及其合作者对调控该物种角生长的发育机制的十年研究的基础上。该项目将培养博士后、研究生和本科生，扩大与日本研究实验室的国际合作，并在地区和国家范围内为高中科学教育和进化生物学和动物行为的公共知识做出贡献。具体地说，PI将结合QTL和分歧作图方法来筛选与武器尺寸增加相关的基因(AIM 1)；对比来自最近分化的短角和长角种群的甲虫增殖角组织中的基因表达，确定差异表达的候选基因和转录本，然后研究它们在这种武器进化中的功能(AIM 2)；他们将使用田间行为研究来比较不同种群中对角的选择强度(AIM 3)。这项研究将通过以下方式影响社会：(1)为冈萨加大学的本科生研究人员建立到华盛顿州立大学和蒙大拿大学工作的渠道；(2)聘请一名高中生物教师参与一个真实的研究项目；(3)在新的米苏拉蝴蝶之家为展示和学生讲解志愿者培训做出贡献；以及(4)针对高中生物学生开展以过程为导向的研究性学习(POGIL)活动。数据将存放在仙女座储存库(http://datadryad.org)，)和Traces(http://trace.ncbi.nlm.nih.gov/Traces/sra/)，NCBI GEO(http://www.ncbi.nlm.nih.gov/geo/info/seq.html)，和GenBank(http://www.ncbi.nlm.nih.gov/genbank/tsa/).

From the horns of Hercules beetles to antlers of elk, intense selection arising from competition for access to reproduction has driven the evolution of extreme animal weapons. Extreme weapons often evolve faster than other body parts, and they tend to be more diverse among species than other body parts. Yet few studies have directly measured selection on weapons in natural populations, and almost nothing is known about the genes and developmental pathways responsible for rapid weapon evolution. This project capitalizes on populations of rhinoceros beetle that differ dramatically in the relative size of a weapon, a "pitchfork" horn projecting from the heads of males. By rigorously studying beetle behavior in divergent populations, the investigators will test whether local differences in the intensity of selection have driven rapid, recent evolutionary changes in weapon size. Studies of the distribution of relevant genes in these populations of beetles, along with identification of additional genes associated with these extreme traits and their location within the genome will further our understanding of the genetic basis of weapon evolution, building on a decade of prior research by these investigators and their collaborators on the developmental mechanisms regulating horn growth in this species. This project will train post-doctoral, graduate, and undergraduate students, expand an international collaboration with research labs in Japan, and contribute both regionally and nationally to high school science education and public knowledge of evolutionary biology and animal behavior. Specifically, the PIs will combine QTL and divergence mapping approaches to screen for genes associated with increased weapon size (AIM 1); contrast gene expression in proliferating horn tissues of beetles from recently diverged short- and long-horned populations, identifying candidate genes and transcripts that are differentially expressed, and then investigating their function in the evolution of this weapon (AIM 2); and they will use field studies of behavior to compare the intensity of selection on horns in divergent populations (AIM 3). This study will impact society through education and outreach by (1) establishing a pipeline for undergraduate researchers from Gonzaga University to work at Washington State University and the University of Montana, (2) engaging a high school biology teacher in an authentic research project, (3) contributing to displays and student docent volunteer training at the new Missoula Butterfly House and (4) developing Process Oriented Guided Inquiry Learning (POGIL) activities targeted to high school biology students. Data will be deposited and available in the Dryad repository (http://datadryad.org), and at Traces (http://trace.ncbi.nlm.nih.gov/Traces/sra/), NCBI GEO (http://www.ncbi.nlm.nih.gov/geo/info/seq.html), and GenBank (http://www.ncbi.nlm.nih.gov/genbank/tsa/).