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完成这个目标。在传统的光转导观点中，不仅氨基酸（AA）位点参与视觉色素的光谱调谐仅位于“视网膜结合袋”或其附近，而且它们还调节最大吸收波长(？最大)的视觉颜料，主要以添加剂的方式。然而，现在很清楚，这两种“假设”在本质上都不成立。因此，为了识别所有关键的AA变化，并了解它们对？因此，必须采取一些新的方法。只有建立光谱调谐的基本原理，才能全面了解视色素（以及色觉）的适应进化的分子机制。