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

在许多生物体中，体型随着纬度的增加而增大。这种模式的出现是因为体型较大的个体在寒冷的环境中更善于保暖，但在温暖的环境中散热的能力较差。这一想法预测，随着气温的上升，生物体将变得更小。尽管许多生物体符合这种模式，但人们对遗传变化或环境条件的潜在生理学和贡献知之甚少。这项研究将考察荷尔蒙在家麻雀迅速改变身体大小方面所起的作用。作为这些研究的一部分，将在两所部落学院和沿纬度梯度的另外三个地点建立家麻雀繁殖巢箱种群。这项研究的一个重要目标是为部落学院的美国印第安人学生提供本科生的研究经验(REU)机会。参加REUS的学生将获得许多好处，包括提高解决问题的技能和增强对STEM学科的保留。然而，典型的REU要求本科生搬迁较长时间，这往往与其他家庭和社区的承诺相冲突。这项研究试图通过在部落大学创造当地的REU机会来克服这一障碍，将对其进行评估，以告知未来有兴趣使用类似方法的教育工作者。此外，美国各地将对家雀进行重新采样，并将创建组织库，历史和当代数据集将被公布，作为未来研究的永久基准。荷尔蒙机制通常影响一系列特征，并有望在形成应对环境变化的生活史策略方面发挥重要作用。这项研究将通过结合历史和新收集的数据和样本、相互移植实验、激素操纵和转录转录来检验这一假说，即胰岛素/胰岛素样信号荷尔蒙网络的变化是一种机制，可以调节家雀身体大小沿纬度梯度的快速变化。这项研究将极大地扩展关于荷尔蒙机制在调节生活史特征的快速表型变化中的作用的已知内容。了解微进化和可塑性反应如何导致荷尔蒙调节的生活史策略的变异，对于预测对环境变化的长期进化反应至关重要。如果荷尔蒙调节的性状在群体间的变异主要是由于激素水平的微进化变化，这有望促进一组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，如果种群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。这项综合研究跨越了从基因表达到种群水平生活史特征变异的分析水平，这样做将增强我们对长期生态模式背后的机制的理解。该项目由综合生态生理学计划和既定的刺激竞争研究计划(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智力优势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.