SG: Uncovering the contributions of albinism to the evolution of the Mexican cavefish

当不同的生物生活在相似的环境中时，相同的特征可以在多个独立的种群中进化。其中一个引人入胜的例子是许多不同洞穴生物色素沉着的减少或丧失。尽管这种模式在野生种群中很常见，但洞穴生物为什么会失去色素还没有得到很好的理解。本研究将研究色素沉着丧失在墨西哥洞穴鱼进化中的作用。为此，该项目将研究色素沉着、大脑中神经递质水平和行为变化之间的关系，这些变化可能对生活在地下的动物有益。这个项目更广泛的影响是利用洞穴鱼系统来增加科学教育的机会。教师们将与研究人员一起开发洞穴鱼生物学的新单元，并将其带回课堂。此外，研究人员将创建一个本科班，让学生获得真实的研究经验。最后，将聘请本科生和研究生参与研究。该项目旨在了解色素减少突变对行为特征的影响。有证据表明，oca2基因的突变是白化病的基础。此外，这些突变可能会影响调节睡眠的神经递质的水平，从而提高了白化病通过减少睡眠时间和促进在营养贫乏的洞穴环境中觅食而有益的可能性。为了验证这一假设，研究小组将把重点放在墨西哥拟南蝽身上。该系统的一些优势包括存在多个独立进化的洞穴种群，以及洞穴和水面鱼类杂交的能力。具体来说，这个项目有三个目标。首先，研究人员将测量多种鱼类体内三种特定神经递质（多巴胺、肾上腺素、去甲肾上腺素）的水平。这些种群包括：1)表层鱼，2)白化（oca2突变体），3)非白化洞穴鱼，4)oca2突变体表层鱼。测量不同鱼类种群的神经递质水平将使研究人员确定神经递质水平的提高是否是色素沉着减少的洞穴鱼的普遍特征。第二个目标是测量野生型和oca2突变的表层鱼的睡眠，以确定oca2在潜在的健康相关特征中的作用。最后，研究人员将通过将洞穴种群和地表种群的个体杂交来产生杂交后代。将测量这些杂交鱼的睡眠、色素沉着和神经递质水平，以确定这些特征之间的遗传关系。因此，该项目将为白化病在洞穴环境中的作用提供新的见解。此外，它将阐明在对新环境的殖民化作出反应时进化的基本原则。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。

When different organisms live in similar environments, the same traits can evolve in multiple, independent populations. One fascinating example of this is the reduction or loss of pigmentation in many different cave organisms. Despite how common this pattern is in wild populations, why cave organisms lose pigmentation is not well understood. This research will study the role of pigmentation loss in the evolution of Mexican cavefish. To do so, the project will examine the relationship between pigmentation, levels of neurotransmitters in the brain, and behavioral changes that may be beneficial to animals living underground. The broader impacts of this project take advantage of the cavefish system to increase access to science education. Teachers will work with the researchers to develop new units on cavefish biology to take back to their classrooms. Additionally, the researchers will create an undergraduate class that will allow students to get authentic research experiences. Finally, undergraduates and graduate students will be hired to participate in the research. This project aims to understand the effects of pigmentation-reducing mutations on behavioral traits. Evidence suggests that mutations in the oca2 gene underlie albinism. Additionally, the mutations may impact levels of sleep-regulating neurotransmitters, raising the possibility that albinism is beneficial by reducing sleep time and promoting foraging in the nutrient-poor cave environment. To test this hypothesis, the research team will focus on A. mexicanus. Some advantages of this system include the existence of multiple, independently evolved cave populations and the ability to hybridize cave and surface fish. Specifically, this project has three aims. First, the researchers will measure levels of three specific neurotransmitters (dopamine, epinephrine, norepinephrine) in multiple populations of fish. Those populations include: 1) surface fish, 2) albino (oca2-mutant), 3) non-albino cavefish, and 4) oca2-mutant surface fish. Measuring neurotransmitter levels in the different fish populations will allow the researchers to determine if enhanced neurotransmitter levels are a general property of cavefish with reduced pigmentation. For the second aim, sleep will be measured in wild-type and oca2-mutant surface fish to determine the role of oca2 in a potentially fitness-related trait. Finally, the researchers will generate hybrids by crossing individuals from cave populations and surface populations. Sleep, pigmentation and neurotransmitter levels will be measured in these hybrid fish to determine the genetic relationship between these traits. Thus, this project will provide new insight into the role of albinism in a cave environment. Further, it will shed light on fundamental principles underlying evolution in response to colonization of a novel environment.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.