title: The evolution of animal chemosensory receptor gene repertoires: roles of chance and necessity.
abstract: Chemosensory receptors are essential for the survival of organisms that range from bacteria to mammals. Recent studies have shown that the numbers of functional chemosensory receptor genes and pseudogenes vary enormously among the genomes of different animal species. Although much of the variation can be explained by the adaptation of organisms to different environments, it has become clear that a substantial portion is generated by genomic drift, a random process of gene duplication and deletion. Genomic drift also generates a substantial amount of copy-number variation in chemosensory receptor genes within species. It seems that mutation by gene duplication and inactivation has important roles in both the adaptive and non-adaptive evolution of chemosensation.
authors.affiliation: Institute of Molecular Evolutionary Genetics and Department of Biology, Pennsylvania State University, 328 Mueller Laboratory, University Park, Pennsylvania 16802, USA. nxm2@psu.edu
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Nei
authors.forename: Yoshihito
authors.initials: Y
authors.lastname: Niimura
authors.forename: Masafumi
authors.initials: M
authors.lastname: Nozawa
mesh_terms: D000818:Animals; D005075:Biological Evolution; D017353:Gene Deletion; D018628:Gene Dosage; D020440:Gene Duplication; D040961:Genetic Drift; D005810:Multigene Family; D009154:Mutation; D011336:Probability; D011544:Pseudogenes; D043562:Receptors, G-Protein-Coupled / Q000235:genetics*; D018035:Receptors, Odorant / Q000235:genetics; D043563:Receptors, Pheromone / Q000235:genetics; D055697:Taste Perception / Q000235:genetics
chemical_list: D043562:Receptors, G-Protein-Coupled; D018035:Receptors, Odorant; D043563:Receptors, Pheromone