Evolution of Avian Photopigments: From Sequences to Color Vision

鸟类感光色素的演变：从序列到色觉

• 批准号: 8005828
• 负责人: Natasha Ivonne Bloch
• 金额: $ 3.5万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-02-01 至 2014-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8005828
• 关键词: Amino Acids; Animals; Binding; Biological Models; Birds; Characteristics; Code; Color; Color Perception; Color Visions; Discrimination; Environment; Evolution; Exhibits; Genes; Genetic; Habitats; Hand; Human; In Vitro; Life; Light; Mammals; Measures; Molecular; Mutation; Natural experiment; Natural regeneration; Opsin; Organism; Positioning Attribute; Property; Research; Retinal Cone; Retinal Pigments; Route; Shapes; Site; Testing; Translating; Variant; Vertebrates; Vision; Visual system structure; Warbler; base; design; improved; public health relevance; research study; vision science; visual stimulus

DESCRIPTION (provided by applicant): Despite being fundamental to vision science, the molecular basis of photopigments' spectral tuning remains poorly understood. Spectral shifts caused by substitutions at any opsin residue depend on genetic background, which means that designing an experiment to elucidate the functional consequences of opsin residue substitutions at each position is impossible. Evolution, on the other hand, has been experimenting on visual systems for millions of years and offers a unique opportunity to understand how spectral shifts occur. Animals live in very diverse light environments and some exhibit a spectacular diversity of colors. Studying how animal visual systems adapt to such variable conditions makes it possible to elucidate visual pigments spectral tuning in vertebrates, including humans (Yokoyama 1997; 2008). Unlike most mammals, birds have excellent color vision, and provide the best model system for uncovering diversity in the visual system of terrestrial vertebrates. However, vision in birds remains understudied. The proposed research aims to evaluate how the visual systems of closely related species of birds have adapted to different conditions and visual stimuli. Complete coding sequences for all cone opsin genes in 15 New World warblers indicate there is substantial amino acid variation in warbler opsins. Nearly 80% of the observed substitutions are in, or adjacent to the binding pocket, and therefore, have the potential to alter the opsins' spectral sensitivity. The functional consequences of mutations at each of these sites will be assessed by regenerating, expressing and measuring the spectral sensitivity of all the observed photopigment variants in vitro. After studying the molecular mechanisms of spectral tuning, we plan to evaluate selective forces that have shaped the evolution of photopigments in birds. Tetrahedral color spaces will be used to evaluate how the observed differences in the photopigments of warblers translate into differences in color perception and discrimination, and how they relate to plumage and habitat properties. This analysis will also test for a possible evolutionary relationship between each species' color vision and the evolved plumage characteristics. The proposed research will fill a significant gap in our understanding of photopigment spectral tuning, thereby contributing to our current understanding of color vision, including the molecular basis of human color vision deficiencies. PUBLIC HEALTH RELEVANCE: Studying how vision evolves in organisms such as birds, is an important route towards improved understanding of human vision and vision deficiencies. Here, "natural experiments" provided by evolution, give us the opportunity to study the mechanisms of spectral tuning in visual pigments.

描述（由申请人提供）：尽管是视觉科学的基础，但对色素光谱调谐的分子基础仍然知之甚少。在任何视蛋白残基的取代所引起的光谱变化取决于遗传背景，这意味着设计一个实验来阐明在每个位置的视蛋白残基取代的功能后果是不可能的。另一方面，进化论已经在视觉系统上进行了数百万年的实验，并提供了一个独特的机会来了解光谱变化是如何发生的。动物生活在非常多样化的光环境中，有些动物表现出壮观的颜色多样性。研究动物视觉系统如何适应这种可变条件，可以阐明脊椎动物（包括人类）的视色素光谱调谐（Yokoyama 1997; 2008）。与大多数哺乳动物不同，鸟类具有出色的色觉，并为揭示陆生脊椎动物视觉系统的多样性提供了最佳模型系统。然而，鸟类的视觉仍然研究不足。这项研究旨在评估密切相关的鸟类物种的视觉系统如何适应不同的条件和视觉刺激。15只新大陆莺的视蛋白基因的完整编码序列表明，莺视蛋白中存在大量的氨基酸变异。近80%的观察到的取代是在结合口袋中或附近，因此，有可能改变视蛋白的光谱灵敏度。将通过体外再生、表达和测量所有观察到的重复色素变体的光谱灵敏度来评估这些位点中的每一个的突变的功能后果。在研究了光谱调谐的分子机制后，我们计划评估塑造鸟类色素进化的选择力。四面体颜色空间将被用来评估观察到的差异，莺的色素转化为颜色感知和歧视的差异，以及它们如何与羽毛和栖息地属性。这项分析还将测试每个物种的色觉和进化的羽毛特征之间可能的进化关系。拟议的研究将填补我们对色素光谱调谐的理解中的一个重大空白，从而有助于我们目前对色觉的理解，包括人类色觉缺陷的分子基础。 公共卫生关系：研究鸟类等生物的视觉如何进化，是提高对人类视觉和视觉缺陷的理解的重要途径。在这里，由进化提供的“自然实验”给了我们研究视色素光谱调谐机制的机会。