Adaptive Evolution of Color Vision

色觉的适应性进化

• 批准号: 8212125
• 负责人: SHOZO YOKOYAMA
• 金额: $ 38.75万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-02-01 至 2016-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8212125
• 关键词: 11 cis Retinal; Amino Acid Sequence; Amino Acids; Animals; Application procedure; Attention; Biological Models; Biology; Cells; Characteristics; Chemicals; Color Visions; Color vision defect; Crustacea; DNA; Disease; Engineering; Environment; Evolution; Fishes; Genetic; Goals; Habitats; Hybrids; Hydrogen Bonding; Learning; Life; Life Style; Light; Measures; Mechanics; Methods; Molecular; Mutagenesis; Mutate; Nucleotides; Organism; Phototransduction; Pigments; Pike fish; Problem Solving; Procedures; Process; Proteins; RH1; Research; Retinal Dystrophy; Retinal Pigments; Retinitis Pigmentosa; Rhodopsin; Sampling; Scientist; Scombridae; Spottings; Squalus acanthias; Structure; Structure-Activity Relationship; Surveys; Testing; Tuna; UV sensitive; Vertebrates; Viola; Vision; absorption; base; fascinate; interest; novel strategies; preconditioning; public health relevance; quantum; research study; vision science

DESCRIPTION (provided by applicant): Animals have diversified and adapted to fill the numerous habitats and environments on this earth. The long-term goal of our studies is to elucidate mechanisms that drive these adaptive changes at the molecular and functional levels. We plan to accomplish this goal using vision as a model system. To identify critical amino acid (AA) changes that modify the wavelengths of maximal absorption (;maxs) of visual pigments, vision scientists analyze "contemporary" pigments. Experimental evolutionary biologists also manipulate "contemporary" pigments and infer the past. However, by ignoring the evolutionary processes of visual pigments, neither the molecular basis of spectral tuning in visual pigments nor the evolutionary mechanisms of visual pigments can be elucidated. Fortunately, the central unanswered questions in phototransduction and evolutionary biology can be solved simultaneously by genetically engineering and manipulating proper "ancestral pigments." Here, we propose to elucidate the molecular mechanisms that drive adaptive evolution of RH2, SWS1, and SWS2 pigments in vertebrates, which have ;maxs of ~450-530, ~355-440, and ~400-460 nm, respectively. We approach the problem not only by determining the molecular basis of spectral tuning in visual pigments but also by establishing the relationships between organisms with different sets of visual pigments and their ecological environments. For each pigment group, we plan to 1) infer the AA sequences of ~15 ancestral pigments and engineer them and determine their ;maxs, 2) infer AA changes that shift the ;max, 3) identify the critical AA changes by mutating ancestral pigments, and 4) establish the universal chemical principle of the spectral tuning in visual pigments by using the quantum mechanical/molecular mechanical (QM/MM) methods, which have been proven to be highly effective. We shall also test the possibility of adaptive evolution of these visual pigments by examining whether the directions of the ;max-shifts of visual pigments in various species match with the changes in the organisms' ecological environments. For this purpose, each of the three pigment groups with variable ;maxs in multiple species will be classified into distinct classes according to their environments and tested for the possibility of adaptive evolution. Since virtually all fish SWS1 pigments examined to date are UV-sensitive, we also plan to search for violet-sensitive SWS1 pigments in different fishes, by surveying fishes that live at depths of 0-200 m and prey on small fishes and do not require UV vision for hunting. Considering the strong AA interactions that occur in SWS1 pigments, we also plan to elucidate how various critical AA changes could have accumulated during its evolution and learn the chemical structural preconditions required for UV pigments to become violet-sensitive and vice versa. PUBLIC HEALTH RELEVANCE: Using cell/molecular and quantum chemical methods, we study the structure-function relationships of visual pigments in various vertebrate species and their ancestors. Various levels of misfoldings of visual pigments induced by different amino acid changes in rhodopsins and other visual pigments are known to cause retinitis pigmentosa and other retinal dystrophies. Hence, the results obtained from our mutagenesis experiments and chemical structural computations of visual pigments together provide the fundamental information on the genetic bases of color vision defects and ocular diseases.

描述（由申请人提供）：动物已经多样化并适应了地球上众多的栖息地和环境。我们研究的长期目标是阐明在分子和功能水平上驱动这些适应性变化的机制。我们计划使用视觉作为模型系统来实现这一目标。为了识别改变视觉色素最大吸收（;maxs）波长的关键氨基酸（AA）变化，视觉科学家分析了“当代”色素。实验进化生物学家还操纵“当代”颜料并推断过去。然而，通过忽略视色素的进化过程，既不能阐明视色素光谱调谐的分子基础，也不能阐明视色素的进化机制。幸运的是，光转导和进化生物学中未解答的核心问题可以通过基因工程和操纵适当的“祖先色素”同时解决。 在这里，我们建议阐明驱动脊椎动物中 RH2、SWS1 和 SWS2 色素适应性进化的分子机制，这些色素的最大值分别为~450-530、~355-440 和~400-460 nm。我们不仅通过确定视觉色素光谱调谐的分子基础来解决这个问题，而且还通过建立具有不同视觉色素组的生物体与其生态环境之间的关系来解决这个问题。对于每个色素组，我们计划 1) 推断约 15 种祖先色素的 AA 序列，对其进行工程设计并确定其最大；2) 推断改变最大的 AA 变化；3) 通过突变祖先色素来识别关键的 AA 变化；4) 通过使用量子力学/分子力学 (QM/MM) 方法建立视色素光谱调谐的通用化学原理，该方法已被证明是非常有效的。我们还将通过检查不同物种中视觉色素的最大移动方向是否与生物体生态环境的变化相匹配来测试这些视觉色素适应性进化的可能性。为此，多个物种中具有可变最大值的三个色素组中的每一个将根据其环境被分为不同的类别，并测试适应性进化的可能性。由于迄今为止检查的几乎所有鱼类 SWS1 色素都对紫外线敏感，因此我们还计划通过调查生活在 0-200 m 深度、捕食小鱼且不需要紫外线视觉进行捕猎的鱼类，在不同鱼类中寻找对紫光敏感的 SWS1 色素。考虑到 SWS1 颜料中发生的强 AA 相互作用，我们还计划阐明各种关键的 AA 变化在其进化过程中如何积累，并了解 UV 颜料变得对紫光敏感所需的化学结构先决条件，反之亦然。 公共健康相关性：利用细胞/分子和量子化学方法，我们研究了各种脊椎动物及其祖先的视色素的结构-功能关系。已知由视紫红质和其他视色素中的不同氨基酸变化引起的不同程度的视色素错误折叠会导致色素性视网膜炎和其他视网膜营养不良。因此，我们的诱变实验和视色素化学结构计算获得的结果共同提供了色觉缺陷和眼部疾病的遗传基础的基本信息。