title: Hox genes in the parasitic platyhelminthes Mesocestoides corti, Echinococcus multilocularis, and Schistosoma mansoni: evidence for a reduced Hox complement.
abstract: Little is known about the Hox gene complement in parasitic platyhelminthes (Neodermata). With the aim of identifying Hox genes in this group we performed two independent strategies: we performed a PCR survey with degenerate primers directed to the Hox homeobox in the cestode Mesocestoides corti, and we searched genomic assemblies of Echinococcus multilocularis and Schistosoma mansoni. We identified two Hox genes in M. corti, seven in E. multilocularis, and nine in S. mansoni (including five previously reported). The affinities of these sequences, and other previously reported Hox sequences from flatworms, were determined according to phylogenetic analysis, presence of characteristic parapeptide sequences, and unusual intron positions. Our results suggest that the last common ancestor of triclads and neodermatans had a Hox gene complement of at least seven genes, and that this was probably derived by gene loss from a larger ancestral Hox complement in lophotrochozoans.
authors.affiliation: Sección Bioquímica, Facultad de Ciencias, Universidad de la República, CP 11400, Montevideo, Iguá, 4225, Uruguay.
authors.forename: Uriel
authors.initials: U
authors.lastname: Koziol
authors.forename: Ana I
authors.initials: AI
authors.lastname: Lalanne
authors.forename: Estela
authors.initials: E
authors.lastname: Castillo
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002590:Cestode Infections / Q000469:parasitology; D048210:Echinococcus multilocularis / Q000235:genetics*; D015801:Helminth Proteins / Q000737:chemistry / Q000235:genetics*; D018398:Homeodomain Proteins / Q000737:chemistry / Q000235:genetics*; D051379:Mice; D008969:Molecular Sequence Data; D010986:Platyhelminths / Q000235:genetics*; D012550:Schistosoma mansoni / Q000235:genetics*; D016415:Sequence Alignment
chemical_list: D015801:Helminth Proteins; D018398:Homeodomain Proteins