title: Eye evolution: common use and independent recruitment of genetic components.
abstract: Animal eyes can vary in complexity ranging from a single photoreceptor cell shaded by a pigment cell to elaborate arrays of these basic units, which allow image formation in compound eyes of insects or camera-type eyes of vertebrates. The evolution of the eye requires involvement of several distinct components-photoreceptors, screening pigment and genes orchestrating their proper temporal and spatial organization. Analysis of particular genetic and biochemical components shows that many evolutionary processes have participated in eye evolution. Multiple examples of co-option of crystallins, Galpha protein subunits and screening pigments contrast with the conserved role of opsins and a set of transcription factors governing eye development in distantly related animal phyla. The direct regulation of essential photoreceptor genes by these factors suggests that this regulatory relationship might have been already established in the ancestral photoreceptor cell.
authors.affiliation: Department of Transcriptional Regulation, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Videnska 1083, Prague 4 CZ 14220, Czech Republic.
authors.forename: Pavel
authors.initials: P
authors.lastname: Vopalensky
authors.forename: Zbynek
authors.initials: Z
authors.lastname: Kozmik
mesh_terms: D000818:Animals; D019143:Evolution, Molecular; D005136:Eye Proteins / Q000235:genetics*; D009799:Ocular Physiological Phenomena / Q000235:genetics*; D017956:Photoreceptor Cells, Invertebrate / Q000502:physiology*; D012168:Retinal Pigments / Q000235:genetics*
chemical_list: D005136:Eye Proteins; D012168:Retinal Pigments