Mechanisms of Color Vision: Genomics, Physiology and Behavior

据推测，地球上有一百多万只动物利用色觉来寻找食物、寻找配偶和避免被捕食者吃掉。这是因为颜色信息比其他类型的视觉线索（如物体的亮度）更可靠。尽管动物们广泛使用颜色来向潜在的配偶宣传，并警告捕食者免受攻击，但科学家们对大多数生物的色觉工作方式知之甚少，包括为什么某些物种的雄性和雌性的色觉不同。这个项目旨在研究一组有毒蝴蝶的视觉，它们的翅膀上呈现出一种新的颜色，紫外光黄色，它们的眼睛里有新的紫色和紫外线感光器。该项目将确定它们基因组的关键部分，这些部分控制着眼睛的发育和眼睛中感光器的位置，这在两性之间是不同的。研究人员将使用行为测试来研究雄性和雌性识别颜色能力的差异，并将其与有助于蝴蝶生存和繁殖的光环境中的线索联系起来。此外，该项目将培养下一代学者——生理学方法的研究生和博士后，这将允许记录动物对光的反应。本科生将接受基因组注释方面的培训。最后，该项目将免费提供一种方法来增加难以研究的光敏蛋白的产量，这可能对各种生物技术应用有用。模仿动物的颜色是在捕食者困惑的背景下进化的。除非模仿动物具有区分模仿颜色的适应性，否则动物本身就有混淆的风险，从而对交配和繁殖产生负面影响。蝴蝶之所以引起人们的兴趣，是因为许多难吃的物种在新热带地区形成了模仿环。研究小组发现，Heliconius的眼睛表达复制的紫外线视蛋白，并表明这种复制可能是通过增强紫外线色觉来适应物种识别。该项目将通过使用免疫组织化学、特征定位和祖先状态重建来追踪光感受器进化的物种和性别特异性模式，从而阐明紫外线视蛋白复制的生物学意义。此外，该项目将利用Heliconius蝴蝶参考基因组以及该项目将生成的其他基因组资源和转录组资源，以识别可能是这些不同谱系中选择目标的眼睛基因以及重复的UV视蛋白基因。这项提议的工作将以前所未有的细节揭示一群密切相关的蝴蝶在日常生活中遇到的信号中颜色视觉的进化。尽管在信号中的两性二态性研究已经有很多，但在感觉系统特别是色觉中的两性二态性研究却几乎没有。这是一个主要的空白，我们现在可以开始用各种方法来填补：Pac-Bio和Illumina dna测序、ATAC-seq、RNA-seq、细胞内电生理学、细胞培养和行为测试。

More than a million animals on the planet are presumed to use color vision to find food, to find mates and to avoid being eaten by predators. This is because color information is more reliable than other kinds of visual cues like an object's brightness. Despite the widespread use of color by animals to advertise to potential mates and to warn predators against attack, scientists know very little about the way color vision works in most organisms, including why color vision differs between males and females in some species. This project aims to examine vision in a group of toxic butterflies that display a new form of coloration on their wings, ultraviolet-yellow, and have novel violet and ultraviolet photoreceptors in their eyes. This project will identify key parts of their genome which control eye development and the placement of photoreceptors in their eyes, which differ between the sexes. The differences in ability between males and females to detect color will be studied using behavioral tests and linked to cues in the butterflies' light environment which contribute to their survival and reproduction. In addition, this project will result in the training of the next generation of scholars - graduate and postdoctoral students in physiological methods, which will permit the recording of an animal's response to light. Undergraduates will be trained in the annotation of genomes. Lastly, the project will make freely-available a method for increasing the production of difficult-to-study light-sensitive proteins, which may be useful for a variety of biotechnology applications. Mimetic animal coloration evolves in the context of predator confusion. Unless mimetic animals have adaptations for discriminating between mimetic colors there is a risk of confusion for the animals themselves, with negative consequences for mating and reproduction. Heliconius butterflies are of interest because many unpalatable species have formed mimicry rings in the Neotropics. The research team has discovered that Heliconius eyes express duplicated ultraviolet (UV) opsins and have shown that this duplication may be an adaptation for species recognition, via enhanced UV color vision. The proposed project will permit the elucidation of the biological significance of the ultraviolet opsin duplication by tracing species- and sex-specific patterns of photoreceptor evolution using immunohistochemistry, character mapping, and ancestral state reconstruction. In addition the project will draw on a Heliconius butterfly reference genome together with other genomic resources and transcriptomic resources that the project will generate, to identify eye genes that may have been the target of selection in these different lineages along with the duplicate UV opsin gene. The proposed work will reveal in unprecedented detail the evolution of color vision within a group of closely-related butterflies in relation to the signals they encounter in their daily lives. Whereas there has been much work on sexual dimorphism in signals, there is virtually no work on sexual dimorphism in sensory systems especially in color vision. This is a major gap that we can now begin to fill using a variety of methods: Pac-Bio and Illumina DNA-sequencing, ATAC-seq, RNA-seq, intracellular electrophysiology, cell culture, and behavioral tests.