Adaptive Evolution of Color Vision

色觉的适应性进化

基本信息

批准号：
7168431
负责人：
SHOZO YOKOYAMA
金额：
$ 37.14万
依托单位：
EMORY UNIVERSITY
依托单位国家：
美国
项目类别：
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

项目摘要

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（由适用提供）：生物会遇到一系列栖息地的潜水员，并适应具有同样多样化的结构和功能的这些环境。我们研究的长期目标是阐明在分子和功能水平上推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。在传统的光转染料视图中，不仅与位于“视网膜结合口袋”或附近的视觉颜料调节相关的氨基酸（AA）位点，而且还可以调节最大滥用（？max）视觉颜料的波长。但是，现在很明显，这些“假设”在本质上都不存在。因此，要确定所有关键的AA变化并了解其个人和协同作用对Max-Shift的影响，必须采取一些新方法。只有当我们建立光谱调整的基本原理时，视觉色素（和色觉）的自适应演变的分子机制才能充分理解。在这里，我们建议将五种深海鱼类兰lamp鱼（S. lecepsarus），Losejaw（A. scintillans），Scabbardfish（L。Fitchf），Thornyhead（S。Altivelis）（S。altivelis）和Viperfish（C. Macouni）克隆所有的视觉色素基因。然后，我们将研究光谱调整的分子碱基和在广泛的脊椎动物种类中视觉颜料的自适应演化的机制。深海鱼类生活在不同的深度，范围为200至4,000 m，在〜480 nm处获得不同水平的阳光。此外，兰菲鱼和毒蛇以〜480的发光发射生物发光，左右jaw散发出〜480和〜700 nm。我们计划探索视觉色素的三个特征：1）视觉色素光谱调整的分子和化学碱基； 2）正面选择的AA变化的统计和实验分析； 3）五种深海鱼类中每种寄生物色素的共同进化。使用理论化学中的计算方法，我们计划测试光谱调整的四个特定假设，并确定确定视觉色素抽象光谱的化学原理。为了测试根据栖息地的光分布在每个物种中同步不同寄生物色素的进化模式，我们将比较核苷酸（或AA）取代的进化速率与同一物种中重复的A和globin基因的进化速率，这也将被克隆和测序。