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: 8242669
• 负责人: Natasha Ivonne Bloch
• 金额: $ 3.58万
• 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/8242669
• 关键词: Amino Acid Sequence; Amino Acids; Animals; Binding; Biological Models; Birds; Characteristics; Code; Color; Color Perception; Color Visions; Data; Discrimination; Environment; Evolution; Exhibits; Genes; Genetic; Habitats; Human; In Vitro; Life; Light; Mammals; Measures; Modeling; Molecular; Mutation; Natural experiment; Natural regeneration; Opsin; Organism; Peptide Sequence Determination; Positioning Attribute; Property; Relative (related person); Research; Retina; Retinal Cone; Retinal Pigments; Role; 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(申请人提供)：尽管是视觉科学的基础，但感光颜料的光谱调谐的分子基础仍然知之甚少。任何视蛋白残基的替换引起的光谱漂移取决于遗传背景，这意味着设计一个实验来阐明每个位置的视蛋白残基替换的功能后果是不可能的。另一方面，进化已经在视觉系统上进行了数百万年的实验，并为理解光谱变化是如何发生的提供了一个独特的机会。动物生活在非常不同的光环境中，有些动物表现出惊人的多样性的颜色。研究动物视觉系统如何适应这种可变的条件，使阐明包括人类在内的脊椎动物的视觉色素光谱调谐成为可能(横山1997；2008)。与大多数哺乳动物不同，鸟类具有极好的色觉，为揭示陆生脊椎动物视觉系统的多样性提供了最佳的模型系统。然而，鸟类的视觉仍未得到充分的研究。这项拟议的研究旨在评估密切相关鸟类的视觉系统如何适应不同的条件和视觉刺激。15只新大陆林莺所有视锥蛋白基因的完整编码序列表明，林莺视蛋白的氨基酸有很大的变异。近80%的观察到的取代位于结合口袋内或邻近结合口袋，因此有可能改变Opsins的光谱敏感性。将通过在体外再生、表达和测量所有观察到的感光变异体的光谱敏感度来评估每个位置突变的功能后果。在研究了光谱调谐的分子机制后，我们计划评估塑造鸟类感光色素进化的选择性力量。将使用四面体颜色空间来评估观察到的林莺感光色素的差异如何转化为颜色感知和辨别的差异，以及它们与羽毛和栖息地属性的关系。这项分析还将测试每个物种的颜色视觉和进化的羽毛特征之间可能存在的进化关系。这项拟议的研究将填补我们对光致色素光谱调谐的理解的一个重大空白，从而有助于我们目前对颜色视觉的理解，包括人类颜色视觉缺陷的分子基础。 公共卫生相关性：研究视力如何在鸟类等生物体中进化，是改善对人类视力和视力缺陷的理解的重要途径。在这里，由进化提供的“自然实验”，让我们有机会研究视觉色素的光谱调谐机制。