title: Gene conversions are under purifying selection in the carcinoembryonic antigen immunoglobulin gene families of primates.
abstract: The carcinoembryonic antigen (CEA) family contains a large number of glycoproteins belonging to the immunoglobulin superfamily. Here, we investigate whether the gene conversions occurring between primate CEA-related genes are adaptive. Our results show that primate CEA-related genes are subject to frequent and repeated gene conversion events. Furthermore, gene conversions occur most frequently between nearby genes sharing similar sequences, are not more frequent in Ig-like V-type 1 domains than in the Ig-like C2-type 1 domains and dN/dS ratio tests shown that both these domains evolve either neutrally or under purifying selection. Our results therefore suggest that CEA-related genes evolve under purifying selection and the frequent gene conversion events we observed likely represent selectively neutral events between genes having similar sequences and functions.
authors.affiliation: Département de Biologie et Centre de Recherche Avancée en Génomique Environnementale, Université d'Ottawa, Ottawa, Ontario K1N 6N5, Canada.
authors.forename: Mouldi
authors.initials: M
authors.lastname: Zid
authors.forename: Guy
authors.initials: G
authors.lastname: Drouin
mesh_terms: D000818:Animals; D002272:Carcinoembryonic Antigen / Q000235:genetics*; D019295:Computational Biology; D030541:Databases, Genetic; D019143:Evolution, Molecular; D005785:Gene Conversion; D005803:Genes, Immunoglobulin; D006801:Humans; D010802:Phylogeny; D011323:Primates / Q000235:genetics*; D012641:Selection, Genetic; D017385:Sequence Homology
chemical_list: D002272:Carcinoembryonic Antigen
keywords: Carcinoembryonic antigen (CEA); Gene conversion; Human; Immunoglobulin; Primates; Purifying selection; Selective constraints