CAREER: Carotenoid coloration in an evolutionary radiation: Connecting molecular function, fitness, and diet ecology in wood warblers

哪些基因决定了近亲物种之间的差异？这些基因的差异是如何转化为不同的特征的？这些特征如何影响个体在生育更多后代方面的成功（即提高适应性）？这些问题是我们理解生物多样性的基础，但人们对它们的理解仍然很少。这个项目旨在明确地将一群被称为林莺的彩色鸣禽的基因、特征和健康联系起来。研究人员先前已经确定了导致这一群体颜色差异的候选基因，特别是那些与类胡萝卜素分子有关的基因。这个项目将测试这些基因差异实际上如何转化为与类胡萝卜素分子相互作用的酶的差异。该项目还将包括对类胡萝卜素颜色不同的鸟类进行实地研究，以研究不同的颜色特征如何影响繁殖。此外，鉴于类胡萝卜素必须从饮食中获得，即鸟类不能自己合成它们——该项目包括本科生研究人员使用分子工具从粪便样本中测试关于鸟类饮食的假设。最后，为了帮助扩大科学参与，激励学生，并吸引他们更多地了解自然世界，该项目将开发一套以鸟类生态和进化为重点的虚拟沉浸式进化生物学体验。该研究项目的重点是林莺（林莺科），这是一种鸟类，有100多种，在过去的1000万年里多样化，是鸣禽中多样化速度最快的鸟类之一。该项目的目标是研究基因的进化史及其功能，这可能与这一群体的多样化有关。目前研究的重点是类胡萝卜素加工基因，特别是β -胡萝卜素加氧酶2 （BCO2）。这种基因与这些鸟类和其他鸟类的羽毛颜色有关，但在驯化物种之外，它还没有功能特征。目标将是表征在莺的辐射中存在的类胡萝卜素，并合成多种BCO2蛋白变体，并测试它们如何在体外与不同的类胡萝卜素底物相互作用。这项工作包括对不同BCO2基因型的蚯蚓林莺进行杂交的实地研究，以测试这些基因型是否对表型有影响。这将需要杂交区域内个体的多代谱系。认识到类胡萝卜素对饮食的依赖性，该项目让本科生研究人员使用分子工具分析杂交区这些鸟类的粪便样本。这允许测试关于鸟类饮食的假设，揭示基因表达、特征和其他生态因素之间的复杂关系。最后，这项工作还包括与宾夕法尼亚州立大学沉浸式体验中心合作，制作一套虚拟现实体验和360度视频，让宾夕法尼亚州中部的高中生和本科生了解野外工作的类型，并教授他们杂交的生物学和遗传学知识。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。

What are the genes that define the differences among closely related species, and how do differences at these genes translate to distinct traits? How do these traits influence the success of individuals in producing more offspring (i.e. increasing fitness)? These questions are fundamental to our understanding of biological diversity but remain poorly understood. This project aims to explicitly link genes, traits, and fitness in a group of colorful songbirds, called wood warblers. The researchers have previously identified candidate genes responsible for differences in coloration in the group, particularly those involving carotenoid molecules. This project will test how those genetic differences actually translate into differences in the enzymes that interact with carotenoid molecules. The project will also include a field study of birds that differ in their carotenoid coloration to study how different coloration traits influence reproduction. In addition, given that carotenoids must be obtained from the diet—i.e. birds cannot synthesize them on their own—the project includes undergraduate researchers using molecular tools to test hypotheses about the diet of birds from fecal samples. Finally, to help broaden participation in science, inspire students, and entice them to learn more about the natural world, the project will develop a set of virtually immersive evolutionary biology experiences focused on avian ecology and evolution.The research project focuses on wood warblers (Parulidae), a family of birds with over 100 species that diversified within the last 10 million years, and which has one of the fastest diversification rates across songbirds. The goal of the project is to study the evolutionary history of genes—and their function—potentially involved in the diversification of this group. The focus of the current study is on carotenoid processing genes, specifically beta carotene oxygenase 2 (BCO2). This gene has been implicated in plumage coloration in these and other birds, yet it has not been functionally characterized outside of domesticated species. The goal will be to characterize the carotenoids present across the radiation of warblers, and also synthesize the multiple BCO2 protein variants and test how they interact in vitro with different carotenoid substrates. The work includes a field study of hybridizing Vermivora warblers, which differ in their BCO2 genotypes, to test whether these have an influence on phenotypes. This will require a multi-generational pedigree of individuals within the hybrid zone. Recognizing the dietary dependence of carotenoids, the project engages undergraduate researchers in using molecular tools to analyze fecal samples from these birds in the hybrid zone. This allows for testing hypotheses about the birds' diets, shedding light on the intricate relationship between gene expression, traits, and other ecological factors. Finally, the work includes a partnership with Penn State’s Center for Immersive Experiences to generate a set of virtual reality experiences and 360-degree videos that will give high-school and undergraduate students in central Pennsylvania a sense of the type of field work, as well as teach them about the biology and genetics of hybridization.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.