Adaptive Evolution of Color Vision

色觉的适应性进化

• 批准号: 7027957
• 负责人: SHOZO YOKOYAMA
• 金额: $ 38.25万
• 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 2011-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7027957
• 关键词: aminoacid; animal genetic material tag; animal population genetics; biochemical evolution; chemical substitution; color visions; fish; gene expression; genetic mapping; light adaptations; molecular cloning; nucleotides; rhodopsin; species difference; statistics /biometry; visual pigments

DESCRIPTION (provided by applicant): Organisms encounter a diverse array of habitats and adapt to these environments with an equally diverse array of structures and functions. 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. In the traditional view of photo-transduction, not only are amino acid (AA) sites that are involved in the spectral tuning of visual pigments located only in or near the "retinal binding pocket" but also they modulate the wavelength of maximal absorption (?max) of visual pigments mostly in an additive fashion. It is now clear, however, that neither of these "assumptions" holds in nature. Hence, to identify all critical AA changes and understand their individual and synergistic effects on the ?max-shift, some new approaches must be taken. Only when we establish the fundamental principle of the spectral tuning, the molecular mechanisms of adaptive evolution of visual pigments (and color vision) will be understood fully. Here we propose to clone all opsin genes of visual pigments of five deep-sea fishes lampfish (S. leucepsarus), loosejaw (A. scintillans), scabbardfish (L. fitchf), thornyhead (S. altivelis), and viperfish (C. macouni). We will then study both the molecular bases of spectral tuning and the mechanisms of adaptive evolution of visual pigments in a wide range of vertebrate species. Living at different depths, ranging from 200 to 4,000 m, the deep-sea fishes receive varying levels of sunlight at ~480 nm. In addition, the lampfish and viperfish emit bioluminescence at ~480 and the loosejaw at ~480 and ~700 nm. We plan to explore three features of visual pigments: 1) the molecular and chemical bases of the spectral tuning of visual pigments; 2) statistical and experimental analyses of positively selected AA changes; and 3) co-evolution of paralogous pigments in each of the five deep-sea fish species. Using computational methods in theoretical chemistry, we plan to test four specific hypotheses of spectral tuning and identify the chemical principles by which absorption spectra of visual pigments are determined. To test whether the evolutionary patterns of different paralogous pigments are synchronized in each species according to the light distribution of the habitat, we shall compare the evolutionary rates of nucleotide (or AA) substitution to those of the duplicated a and ¿-globin genes in the same species, which will also be cloned and sequenced.

描述（由申请人提供）：生物体遇到各种各样的栖息地，并以同样多样化的结构和功能适应这些环境。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。在传统的光转导观点中，不仅参与视色素光谱调谐的氨基酸（AA）位点位于“视网膜结合袋”中或附近，而且它们还调节最大吸收波长（？）max）的视觉色素，主要是以添加剂的方式。然而，现在很清楚，这些“假设”在本质上都不成立。因此，要确定所有关键的AA变化，并了解他们的个人和协同效应？最大移位，必须采取一些新的方法。只有确立了光谱调谐的基本原理，才能充分理解视色素（和色觉）适应性进化的分子机制。 本研究拟克隆五种深海鱼类视色素的全部视蛋白基因。leucepsarus）、松颌A.鱼（L. fitchf）、刺头草S. altivelis）和蝰鱼C.马库尼）。然后，我们将研究光谱调谐的分子基础和视色素在各种脊椎动物物种中的适应性进化机制。深海鱼类生活在不同的深度，从200米到4,000米不等，它们接受不同程度的480纳米左右的阳光。此外，灯鱼和毒蛇鱼在~480 nm处发出生物发光，松颌鱼在~480 nm和~700 nm处发出生物发光。我们计划探索视色素的三个特征：1）视色素光谱调谐的分子和化学基础; 2）积极选择AA变化的统计和实验分析; 3）五种深海鱼类中旁系同源色素的共同进化。使用理论化学中的计算方法，我们计划测试光谱调谐的四个具体假设，并确定确定视色素吸收光谱的化学原理。为了测试不同旁系同源色素的进化模式是否根据栖息地的光分布在每个物种中同步，我们将比较核苷酸（或AA）替换的进化速率与同一物种中重复的α和<$-珠蛋白基因的进化速率，这也将被克隆和测序。