title: Evolution and functional divergence of monocarboxylate transporter genes in vertebrates.
abstract: Monocarboxylate transporters (MCTs) form a gene family with an ancient past. The identification of MCTs (MCHs) from bacteria, protozoa, fungi, invertebrates, as well as vertebrates, but not from plants and virus, allowed illuminating the phylogenetic and evolutionary history of this gene family. The significant expansion of vertebrate MCT genes should have primarily occurred after the divergence of vertebrates and invertebrates, but before the divergence time between ray-finned fish and mammals. The divergence of insect MCTs should have at least occurred in the common ancestor of fruit fly, beetle, and honeybee. Fungi monocarboxylate transporter homologues (MCHs) might evolve independently from an ancient ancestor. The results of functional divergence analysis provided statistical evidences for shifted evolutionary rate and/or changes of amino acid property after gene duplication. The sliding window analysis of the d(N)/d(S) ratio values showed that strong functional constraints must impose on the N- and C-terminal domains of vertebrate MCTs. These corresponding regions may play crucial roles for functionality of MCT proteins.
authors.affiliation: School of Agricultural and Food Science, Zhejiang Forestry University, Lin'an, Hangzhou 311300, China. liuqp@genomics.org.cn
authors.forename: Qingpo
authors.initials: Q
authors.lastname: Liu
authors.forename: Shijuan
authors.initials: S
authors.lastname: Dou
authors.forename: Guang'en
authors.initials: G
authors.lastname: Wang
authors.forename: Zhimin
authors.initials: Z
authors.lastname: Li
authors.forename: Ying
authors.initials: Y
authors.lastname: Feng
mesh_terms: D000818:Animals; D019143:Evolution, Molecular; D020440:Gene Duplication; D006801:Humans; D027501:Monocarboxylic Acid Transporters / Q000737:chemistry / Q000235:genetics*; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D013045:Species Specificity; D027981:Symporters / Q000737:chemistry / Q000235:genetics; D014714:Vertebrates / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D000099233:Monocarboxylate Transport Protein 1
chemical_list: D027501:Monocarboxylic Acid Transporters; D027981:Symporters; D000099233:Monocarboxylate Transport Protein 1