Evolution of melanopsin photoreceptors: discovery and characterization of a new melanopsin in nonmammalian vertebrates.

ABSTRACT: In mammals, the melanopsin gene (Opn4) encodes a sensory photopigment that underpins newly discovered inner retinal photoreceptors. Since its first discovery in Xenopus laevis and subsequent description in humans and mice, melanopsin genes have been described in all vertebrate classes. Until now, all of these sequences have been considered representatives of a single orthologous gene (albeit with duplications in the teleost fish). Here, we describe the discovery and functional characterisation of a new melanopsin gene in fish, bird, and amphibian genomes, demonstrating that, in fact, the vertebrates have evolved two quite separate melanopsins. On the basis of sequence similarity, chromosomal localisation, and phylogeny, we identify our new melanopsins as the true orthologs of the melanopsi

SUBMITTER: Bellingham J 

PROVIDER: S-EPMC1514791 | biostudies-literature | 2006 Jul

REPOSITORIES: biostudies-literature