URoL: Epigenetics 2: Collaborative Research: Bumble bee cold tolerance across elevations - From epigenotype to phenotype across space, time, and levels of biological organization

了解生物体如何应对环境变化在生态学和进化生物学中具有根本的重要性。对环境变化的适应通常是通过检查生物体的外观（表型）及其DNA序列（基因型）在广泛的气候条件下如何变化来推断的。然而，人们越来越多地认识到，在基因组到表型的谱系中，还有其他复杂的层次，它们通过改变遗传变异的表达来影响对环境的反应。表观遗传，或非DNA序列为基础，DNA修饰在不同的环境条件下越来越被认为是一个强有力的机制，可能驱动生物体如何应对不同的环境。同样，与代谢活动相关的不同分子（代谢组）可以在不同环境下的个体或群体中变化，或者可以在压力条件下改变生物体功能。跨海拔的物种在短空间尺度上经历了条件的快速变化，特别是温度的变化，这为梳理不同机制如何影响环境变化的耐受性提供了优势。该项目将重点研究野生和实验室饲养的大黄蜂在不同海拔的耐热性，大黄蜂是一种受环境压力威胁的重要传粉昆虫。该项目将为了解蜜蜂种群如何克服环境压力提供有价值的工具，这将有助于预测蜜蜂种群的稳定性。阿拉巴马大学、塔斯卡卢萨大学和怀俄明大学的博士后、研究生和本科生将接受分子生物学、生理学和计算建模方法方面的广泛培训。一款策略游戏应用程序将为K-12学生开发，以展示分子变化如何影响不同温度条件下的人口和生态系统。这项研究的结果将通过在犹他州斯托克斯自然中心的一个本地蜂园的展览来传播，以提高人们对野生传粉媒介的认识。该项目的主要研究目标是解决以下问题：信息是如何从遗传和表观遗传变异中通过表达这些信息来产生适应非生物极端的种内表型的？对俄勒冈州喀斯喀特山脉海拔梯度上野外采集和实验室饲养的大黄蜂进行的热生理实验将与基因组学、转录组学、甲基组学和代谢组学分析相结合。计算模型将用于整合数据集，并测试在低温暴露下，不同人群DNA表观遗传修饰的变化如何影响基因表达，并最终影响生理。具体的研究问题包括：(1)无论地理来源如何，大黄蜂是否能够承受类似的冷应激暴露，或者个体、社会种姓和种群在耐寒性方面是否表现出与当地气候相关的结构性差异？(2)群体在不同环境下表现出的DNA甲基化、转录和代谢组学的结构性差异，以及对冷应激反应过程的可塑性调节，在多大程度上？(3)个体生物内的表观遗传变化如何影响转录，进而影响小分子的产生，从而解释个体、种姓、菌落和环境之间耐寒性的差异？该奖项反映了美国国家科学基金会的法定使命，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。

Understanding how organisms cope with environmental variability is of fundamental importance in ecology and evolutionary biology. Adaptation to environmental variation has commonly been inferred by examining how the appearance of organisms (phenotypes) and their DNA sequences (genotypes) vary across a broad range of climatic conditions. However, there has been increasing recognition of additional layers of complexity along the genome-to-phenotype spectrum that influence responses to the environment by altering expression of genetic variation. Epigenetic, or non-DNA sequence based, DNA modifications under different environmental conditions are increasingly considered to be a potent mechanism that may drive how organisms respond to different environments. Likewise, the different molecules associated with metabolic activity (metabolome) can vary among individuals or populations in different environments or can change under stressful conditions to alter organism function. Species that occur across altitudes experience rapid shifts in conditions, especially temperature, over short spatial scales, which provides advantages for teasing apart how different mechanisms influence tolerance of environmental variation. This project will focus on thermal tolerance across elevations in wild and laboratory reared bumble bees, an important group of pollinators that are threatened by environmental pressures. The project will provide valuable tools to understand how bee populations overcome environmental stress that will help predict the stability of bee populations. Post-doctoral fellows, graduate students and undergraduates at the University of Alabama, Tuscaloosa and University of Wyoming will be broadly trained in molecular biology, physiology and computational modeling approaches. A strategy game app to demonstrate how molecular changes can affect populations and ecosystems under different thermal conditions will be developed for K-12 students. Results of the study will be disseminated through an exhibit at a native bee garden within the Stokes Nature Center in Utah to increase awareness of wild pollinators.The major research goal of the project is to address the question: How does information flow from genetic and epigenetic variation through expression of this information to produce intraspecific phenotypes adapted to abiotic extremes? Thermal physiology experiments on field-collected and laboratory-reared bumble bees from elevation gradients in the Oregon Cascade Mountains will be combined with genomic, transcriptomic, methylomic, and metabolomic analyses. Computational modeling will be employed to integrate data sets and test how variation in epigenetic modification of DNA in different populations influences gene expression, and ultimately physiology, under cold temperature exposure. Specific research questions include: (1) are bumble bees capable of withstanding similar cold stress exposure regardless of geographic origin, or do individuals, social castes, and populations exhibit constitutive variation in cold tolerance associated with local climate? (2) to what degree do populations exhibit structured variation in DNA methylation, transcription, and metabolomics across environments versus plastic regulation of processes in response to cold stress?, and (3) how do epigenetic changes within individual organisms influence transcription and in turn production of small molecules to explain variation in cold tolerance across individuals, castes, colonies, and environments?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.