CAREER: Rapid phenotypic divergence and insulin-like growth factor 1 (IGF-1) signaling in a widespread songbird

在许多生物中，身体大小随纬度增加而增加。这种模式的发生是因为较大的个体在寒冷的环境中更善于保持热量，但在温暖的环境中散热较差。这一观点预测，生物体将随着温度的升高而变小。虽然许多生物体符合这一模式，但对遗传变化或环境条件的潜在生理学和贡献知之甚少。这项研究将研究激素在麻雀快速变化的身体大小中所起的作用。作为这些研究的一部分，将在两个部落学院和沿着纬度梯度的另外三个地点建立家雀的繁殖巢箱种群。这项研究的一个重要目标是为部落学院的美国印第安学生提供本科生（REU）研究经验的机会。参加雷乌斯的学生将获得许多好处，包括提高解决问题的能力和提高STEM学科的保留率。然而，典型的雷乌斯要求本科生搬迁很长一段时间，这往往与其他家庭和社区的承诺冲突。该研究旨在通过在部落学院创造当地REU机会来克服这一障碍，这些机会将被评估，以告知未来有兴趣使用类似方法的教育工作者。此外，将在美国各地对家雀进行重新采样，并将建立一个组织库，同时公布历史和当代数据集，作为未来研究的永久基准。激素机制通常会影响一系列特征，并有望在塑造生活史策略以应对环境变化方面发挥重要作用。这项研究将测试的假设，胰岛素/胰岛素样信号激素网络的变化是一种机制，介导的身体大小的快速变化沿着一个纬度梯度在家麻雀使用的组合的历史和新收集的数据和样本，相互移植实验，激素操纵，和转录组学。这项研究将极大地扩展已知的激素机制在介导生活史性状快速表型变异中的作用。了解微进化和可塑性反应如何影响植物介导的生活史策略的变化，对于预测环境变化的长期进化反应至关重要。如果在群体中，激素介导的性状的变异主要是由于激素水平的微进化变化，这有望促进一套对配体敏感的性状的快速进化，但同时限制这些性状的独立进化。或者，如果群体水平的变化主要是由于性状特异性受体密度的微进化变化，性状可能独立进化。相反，如果大部分变化是由于发育可塑性，长期反应预计将更加有限。这项综合性研究跨越了从基因表达到生活史特征的群体水平变化的分析水平，这样做将提高我们对长期存在的生态模式的机制的理解。该项目由综合生态生理学计划和刺激竞争研究的既定计划（EPSCoR）共同资助该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

In many organisms, body size increases with latitude. This pattern occurs because larger individuals are better at retaining heat in cold environments, but worse at dissipating heat in warm environments. This idea predicts that organisms will get smaller in response to rising temperatures. Although many organisms fit this pattern, the underlying physiology and contribution of genetic changes or environmental conditions is poorly understood. The research will examine the role hormones play in rapidly changing body size in house sparrows. As part of these studies, breeding nest-box populations of house sparrows will be established at two tribal colleges and three additional sites along a latitudinal gradient. An important goal of the study is to provide Research Experience for Undergraduate (REU) opportunities for American Indian students at tribal colleges. Students that participate in REUs experience numerous benefits including increased problem solving skills and enhanced retention in STEM disciplines. However, typical REUs require undergraduates to relocate for extended periods of time, which often conflicts with other family and community commitments. The study seeks to overcome this barrier by creating local REU opportunities at tribal colleges, which will be assessed to inform future educators interested in using similar approaches. In addition, house sparrows will be re-sampled at sites throughout the U.S. and a tissue bank will be created and both historical and contemporary datasets will be published to serve as a permanent benchmark for future studies. Hormonal mechanisms commonly influence suites of traits and are expected to play an important role in shaping life-history strategies in response to environmental change. The research will test the hypothesis that variation in the insulin/insulin-like signaling hormonal network is a mechanism that mediates rapid shifts in body size along a latitudinal gradient in house sparrows using a combination of historical and newly collected data and samples, a reciprocal transplant experiment, a hormonal manipulation, and transcriptomics. The research will greatly extend what is known about the role of hormonal mechanisms in mediating rapid phenotypic variation in life history traits. Knowledge of how micro-evolutionary and plastic responses contribute to variation in hormonally mediated life history strategies is essential for predicting long-term evolutionary responses to environmental change. If among population variation in hormonally mediated traits is primarily due to micro-evolutionary changes in hormone levels, this is expected to facilitate the rapid evolution of a suite of traits sensitive to the ligand, but to simultaneously limit the independent evolution of these traits. Alternatively, if population level variation is primarily due to micro-evolutionary changes in trait specific receptor densities, traits may evolve independently. If instead, most of the variation is due to developmental plasticity, long-term responses are expected to be more limited. This integrative study spans levels of analyses from gene expression to population level variation in life-history traits and in doing so will enhance our understanding of the mechanisms that underlie a long standing ecological pattern.This project is jointly funded by the Integrative Ecological Physiology Program and the Established Program to Stimulate Competitive Research (EPSCoR).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.