EVOLUTIONARY GENETICS OF VERTEBRATE VISION

视觉通过影响生物体的生存，对生物体的进化有着深远的影响。这项研究的长期目标是阐明视觉中最基本的分子--视色素的结构-功能关系的进化变化。该建议集中于适应性进化的分子基础，考虑1）红色和绿色（红色/绿色）色觉，2）紫外（UV）视觉，和3）视色素的视杆细胞和视锥细胞特异性。色觉和感光细胞特异性的特征在于使用波长的最大反射（λ max）和再生率和分解的视色素，分别。本研究将利用金鱼红、绿色视蛋白研究红/绿色色觉适应性进化的遗传和分子基础。auratus）、山羊（C. hircus）、白尾鹿（O. virginianus）、欧洲兔（O. cuniculus）、大鼠（R. norvegicus）、灰松鼠（S. carolinensis）、豚鼠（C. porcellus）和灵长类动物，它们在大约510-560 nm处代表整个红/绿色光谱。本研究拟利用金鱼、美洲变色龙（A。carolinensis）、波多黎各蜥蜴（A. cristatellus和A. gundlachi）、Tokay gecko（G. gekko）、鸽子（C. livia）、鸡（G. gallus）、大鼠和小鼠（M. musculus），其λ max值范围为360至420 nm。对于这两种分析，我们将首先预测可能导致视色素λ max偏移的潜在重要氨基酸变化。通过定点诱变或以嵌合形式衍生的野生型和突变体视蛋白将在培养的COS 1细胞中表达，并用11-顺式视黄醛重建。评估所得颜料的λ max值，我们将研究氨基酸变化对λ max位移的影响。研究美国变色龙和Tokay壁虎视色素的再生率和羟胺敏感性，我们还将研究不仅负责视色素的感光细胞特异性，而且负责视色素对纯视杆细胞和纯视锥细胞环境的适应过程的分子机制。

Vision has profound effects on evolution of organisms by affecting survivorship through such basic behaviors as mate choice and foraging strategies. The long-term goal of the proposed research is to elucidate evolutionary changes of the structure-function relationships of the most basic molecules in vision, visual pigments. This proposal focuses on the molecular bases of adaptive evolution considering l) red and green (red/green) color vision, 2) ultraviolet (UV) vision, and 3) rod- and cone- specificities of visual pigments. Color vision and the photoreceptor cell specificity are characterized by using wavelength of maximal absorptions (lambda max) and rates of regeneration and decomposition of visual pigments, respectively. The genetics and molecular bases of adaptive evolution of red/green color vision will be studied using the red and green opsins of goldfish (C. auratus), goat (C. hircus), white-tailed deer (O. virginianus), European rabbit (O. cuniculus), rat (R. norvegicus), gray squirrel (S. carolinensis), guinea pig (C. porcellus), and primates that represent the entire red/green spectra at approximately 510-560 nm. The genetics and adaptive evolution of UV vision will be studied by using UV opsins of goldfish, American chameleon (A. carolinensis), Puerto Rican lizards (A. cristatellus and A. gundlachi), Tokay gecko (G. gekko), pigeon (C. livia), chicken (G. gallus), rat, and mouse (M. musculus), whose lambda max values range from 360 to 420 nm. For both analyses, we will first predict potentially important amino acid changes that may cause lambda max-shifts of the visual pigments. Wild type and mutant opsins, derived by site-directed mutagenesis or in chimeric forms, will be expressed in cultured COS1 cells, and reconstituted with 11-cis retinal. Evaluating lambda max values of the resulting pigments, we will study the effects of amino acid changes on the lambda max-shifts. Studying rates of regeneration and hydroxylamine sensitivities of visual pigments of American chameleon and Tokay gecko, we will also study the molecular mechanisms responsible not only for photoreceptor specificities of visual pigments but also for adaptive processes of visual pigments to the pure-rod and pure cone environments.