Adaptive Evolution of Color Vision

生物遇到各种各样的栖息地，并以同样多样的方式适应这些环境。 一系列的结构和功能。我们研究的长期目标是阐明 这些适应性的变化在分子和功能水平。我们计划使用Vision来实现这一目标 作为一个模型系统。在光诱导的传统观点中，不仅是氨基酸（AA）位点， 参与仅位于“视网膜结合袋”中或附近的视色素的光谱调谐， 它们对视色素最大吸收波长（λ max）的调节主要是相加作用。 然而，现在很清楚，这些“假设”在本质上都不成立。因此，为了确定所有关键AA 改变和了解他们的个人和协同效应的Xmax转变，一些新的方法 必须采取。只有当我们确立了光谱调谐的基本原理， 将充分理解视色素（和色觉）的适应性进化机制。 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自适应的机制， 视觉色素在脊椎动物物种中的进化。生活在不同的深度， 在200至4,000米的高度，深海鱼类接受到不同程度的约480 nm的阳光。此外，灯鱼 蝰蛇鱼在~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 色素; 2）积极选择AA变化的理论和实验分析; 3） 这五种深海鱼类中的每一种都含有旁系同源色素。在理论上使用计算方法 化学，我们计划测试光谱调谐的四个具体假设，并确定化学原理， 确定视色素的吸收光谱。为了测试人类的进化模式 不同的旁系同源色素在每个物种中是同步的， 栖息地，我们将比较核苷酸（或AA）取代的进化速率， a和β珠蛋白基因的克隆和序列分析。

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 phototfansduction, 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 (Xmax) of visual pigments mostly in an additivefashion. 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 Xmax-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) statisticaland experimental analysesof 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 paralogouspigments are synchronized in each species according to the light distribution of the habitat, we shall comparethe evolutionary rates of nucleotide (or AA) substitution to those of the duplicated a and (3 globin genes in the same species, which will also be cloned and sequenced.