Vision has profound effects on the evolution of organisms by affecting survivorship through such basic behaviors as mate choice and foraging strategies. Its importance is strongly indicated by the presence of visual pigments in a whole array of organisms ranging from bacteria to human. Here, we propose to continue our molecular evolutionary analyses by using a diverse range of species: marine lamprey (Petromyzon marinus), coelacanth (Latemeria chalumnae), American chameleon (Anolis carolinensis), and pigeon (Columba livia). Using these species, we plan to investigate molecular genetic mechanisms that underlie the processes of dim and color visions in vertebrates. By constructing genomic DNA libraries, cloning and nucleotide sequencing, we plan to characterize all opsin genes from these species. These sequence and other available opsin gene sequences will be subjected to extensive phylogenetic analyses. From statistical analyses, we intend to learn the processes of the opsin gene evolution, including gene duplications and functional differentiations of the orthologous and paralogous opsin genes in vertebrates. Using information collected from sequence comparisons and knowledge of naturally-occurring species-specific wavelength of maximal absorptions (lambda-max), we will also identify the potentially important amino acid (and nucleotide) substitutions which may cause changes in the lambda-max values. The opsin genes found will be expressed in cultured COS cells, reconstituted with 11-cis-retinal, and measured for the absorption spectra of the opsins encoded. The effects of the unique nucleotide (and amino acid) substitutions will be investigated by generating mutants using site- directed mutagenesis and conducting the COS cell expression experiments. In this way, we will rigorously evaluate the effects of specific nucleotide substitutions on the functional changes of any opsin.

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National Institute of General Medical Sciences (NIGMS)
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Genetics Study Section (GEN)
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Syracuse University
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Yokoyama, Shozo; Takenaka, Naomi; Agnew, Dalen W et al. (2005) Elephants and human color-blind deuteranopes have identical sets of visual pigments. Genetics 170:335-44
Hiramatsu, Chihiro; Radlwimmer, F Bernhard; Yokoyama, Shozo et al. (2004) Mutagenesis and reconstitution of middle-to-long-wave-sensitive visual pigments of New World monkeys for testing the tuning effect of residues at sites 229 and 233. Vision Res 44:2225-31
Deeb, Samir S; Wakefield, Matthew J; Tada, Takashi et al. (2003) The cone visual pigments of an Australian marsupial, the tammar wallaby (Macropus eugenii): sequence, spectral tuning, and evolution. Mol Biol Evol 20:1642-9
Yokoyama, Shozo; Tada, Takashi (2003) The spectral tuning in the short wavelength-sensitive type 2 pigments. Gene 306:91-8
Yokoyama, Shozo (2002) Molecular evolution of color vision in vertebrates. Gene 300:69-78
Yokoyama, S; Radlwimmer, F B (2001) The molecular genetics and evolution of red and green color vision in vertebrates. Genetics 158:1697-710
Yokoyama, S; Blow, N S (2001) Molecular evolution of the cone visual pigments in the pure rod-retina of the nocturnal gecko, Gekko gekko. Gene 276:117-25
Kawamura, S; Hirai, M; Takenaka, O et al. (2001) Genomic and spectral analyses of long to middle wavelength-sensitive visual pigments of common marmoset (Callithrix jacchus). Gene 269:45-51
Yokoyama, S; Shi, Y (2000) Genetics and evolution of ultraviolet vision in vertebrates. FEBS Lett 486:167-72
Yokoyama, S (2000) Molecular evolution of vertebrate visual pigments. Prog Retin Eye Res 19:385-419

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