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。其中一个有趣的例子是许多不同洞穴生物中色素沉着的减少或消失。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沉着还不是很清楚。本研究将研究色素缺失在墨西哥穴居鱼进化中的作用。为此，该项目将研究色素沉着、大脑中神经递质水平以及可能有利于生活在地下的动物的行为变化之间的关系。该项目的更广泛影响是利用洞穴鱼系统增加获得科学教育的机会。教师将与研究人员合作，开发新的洞穴生物学单元，带回课堂。此外，研究人员将创建一个本科生班级，让学生获得真实的研究体验。最后，将聘请本科生和研究生参与研究。这个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基因突变是白化病的基础。此外，这些突变可能会影响睡眠调节神经递质的水平，增加了白化病通过减少睡眠时间和促进在营养不良的洞穴环境中觅食而受益的可能性。为了验证这一假设，研究小组将重点研究墨西哥文昌鱼。这个系统的一些优势包括存在多个独立进化的洞穴种群，以及使洞穴鱼类和表层鱼类杂交的能力。具体地说，这个项目有三个目标。首先，研究人员将测量多个鱼类种群中三种特定神经递质(多巴胺、肾上腺素和去甲肾上腺素)的水平。这些种群包括：1)表层鱼，2)白化(OCA2突变)，3)非白化穴居鱼，以及4)OCA2突变表层鱼。测量不同鱼类种群中的神经递质水平将使研究人员能够确定神经递质水平增强是否是色素沉着减少的穴居鱼的普遍特征。对于第二个目的，将测量野生类型和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。将对这些杂交鱼类的睡眠、色素和神经递质水平进行测量，以确定这些特征之间的遗传关系。因此，这个项目将为白化病在洞穴环境中的作用提供新的见解。此外，它还将阐明应对新环境殖民而进行进化的基本原则。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。

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.