title: Evolution of vertebrate central nervous system is accompanied by novel expression changes of duplicate genes.
abstract: The evolution of the central nervous system (CNS) is one of the most striking changes during the transition from invertebrates to vertebrates. As a major source of genetic novelties, gene duplication might play an important role in the functional innovation of vertebrate CNS. In this study, we focused on a group of CNS-biased genes that duplicated during early vertebrate evolution. We investigated the tempo-spatial expression patterns of 33 duplicate gene families and their orthologs during the embryonic development of the vertebrate Xenopus laevis and the cephalochordate Brachiostoma belcheri. Almost all the identified duplicate genes are differentially expressed in the CNS in Xenopus embryos, and more than 50% and 30% duplicate genes are expressed in the telencephalon and mid-hindbrain boundary, respectively, which are mostly considered as two innovations in the vertebrate CNS. Interestingly, more than 50% of the amphioxus orthologs do not show apparent expression in the CNS in amphioxus embryos as detected by in situ hybridization, indicating that some of the vertebrate CNS-biased duplicate genes might arise from non-CNS genes in invertebrates. Our data accentuate the functional contribution of gene duplication in the CNS evolution of vertebrate and uncover an invertebrate non-CNS history for some vertebrate CNS-biased duplicate genes.
authors.affiliation: State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Jiaochang East Road 32, Kunming 650223, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Chen
authors.forename: Yun
authors.initials: Y
authors.lastname: Ding
authors.forename: Zuming
authors.initials: Z
authors.lastname: Zhang
authors.forename: Wen
authors.initials: W
authors.lastname: Wang
authors.forename: Jun-Yuan
authors.initials: JY
authors.lastname: Chen
authors.forename: Naoto
authors.initials: N
authors.lastname: Ueno
authors.forename: Bingyu
authors.initials: B
authors.lastname: Mao
mesh_terms: D000663:Amphibians / Q000235:genetics; D000818:Animals; D002490:Central Nervous System / Q000378:metabolism*; D019143:Evolution, Molecular; D020440:Gene Duplication; D020869:Gene Expression Profiling; D020131:Genes, Duplicate; D006801:Humans; D010802:Phylogeny; D014714:Vertebrates / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D014981:Xenopus / Q000235:genetics