MOLECULAR EVOLUTION OF VISUAL PIGMENT GENES IN ASTYANAX

视觉通过影响生物的进化对生物的进化产生深远的影响 通过交配偏好、觅食等基本行为生存 策略和猎物偏好。它的重要性从以下几个方面得到了强烈的表明 视觉色素在一系列生物体中的存在，从 细菌对人类的影响。利用洞穴盲鱼和有眼河鱼 Characid，Astianax Fasciatus，我们建议研究其分布格局。 获得的核苷酸和氨基酸将有助于理解 功能适应和可能的视力退化。 通过构建基因组DNA文库、克隆和核苷酸测序 并使用聚合酶链式反应(PCR)和直接测序，我们 计划表征所有盲穴鱼和洞穴鱼的视觉色素基因 有眼睛的河鱼。此外，我们将确定哪些视觉色素基因 表达在河鱼的眼睛和松果体器官中 两种鱼。这将通过cdna的聚合酶链式反应扩增来实现。 由这些器官的RNA制成，然后直接测序。DNA 所获得的序列将用于评估该病毒的生物学意义 通过考虑以下统计数据来累积突变：(1) 过渡性和横向变化，(2)核苷酸比率 替代，(3)同义和非同义变化的比率，以及(4) 密码子用法。这些数量将通过考虑不同的 视觉色素的功能域，即细胞内， 细胞外，和七个跨膜片段，将用于 构建系统发育树并估计不同物种的长度 树枝。核苷酸和氨基酸的起源、方向和速度 还将对替换进行评估。此外，这些和其他 鸟嘌呤核苷酸结合蛋白偶联受体基因序列将 用于对中性进化和适应性进化进行推理。

Vision has profound effects on the evolution of organisms by affecting survivorship through such basic behaviors as mating preference, foraging strategies and prey preference. Its importance is strongly indicated by the presence of visual pigments in a whole array of organisms ranging from bacteria to human. Using both blind cave fish and eyed river fish of the characid, Astyanax fasciatus, we propose to investigate the patterns of nucleotide and amino acid obtained will contribute in understanding functional adaptation and possible degeneration of vision. By constructing genomic DNA libraries, cloning and nucleotide sequencing and using the polymerase chain reaction (PCR) and direct sequencing, we plan to characterize all visual pigment genes from both blind cave fish and eyed river fish. In addition, we will determine which visual pigment genes are expressed in the eyes of the river fish and the pineal organs of the two types of fish. This will be achieved using PCR amplification of cDNA made from RNA of these organs followed by direct sequencing. The DNA sequences obtained will be used to evaluate the biological implications of the mutation accumulations by considering statistics such as (1) rates of transitional and transversional changes, (2) rates of nucleotide substitution, (3) rates of synonymous and nonsynonymous changes, and (4) codon usage. These quantities will be evaluated by considering different functional domains of the visual pigments, i.e., intracellular, extracellular, and seven transmembrane segments and will be used to construct phylogenetic trees and to estimate the lengths of the different branches. Origin, direction, and speed of nucleotide and amino acid substitutions will also be evaluated. Furthermore, these and other sequences of guanine nucleotide binding protein coupled receptor genes will be used to make inference on the neutral as well as adaptive evolutions.