title: ParaHox gene expression in the polychaete annelid Capitella sp. I.
abstract: Hox and ParaHox genes are transcriptional regulators vital for many aspects of embryonic development in bilaterian animals and are considered to have originated from one ancestral proto-Hox/ParaHox cluster. Hox genes are clustered in the genome of both protostomes and deuterostomes, and there is a specific relationship between the position of a gene in the cluster and the position of its expression along the animal body axis (colinearity). It is not clear whether the ParaHox genes Gsx, Xlox, and, Cdx generally exhibit a similar phenomenon since developmental expression for all three ParaHox genes within a single species has not yet been described for any protostome animal. Here we show the spatial and temporal localization for all three ParaHox genes in the polychaete Capitella sp. I, a member of one of the morphologically most diverse and understudied groups within the Metazoa, the Lophotrochozoa. Our data demonstrate that although both CapI-Xlox and CapI-Cdx are regionally expressed in the gut, the three Capitella sp. I ParaHox genes as a group do not perfectly fit predictions of temporal or spatial colinearity. Instead, there is a conservation of expression across species associated with development of particular tissues, and the relative order of initiation of ParaHox gene expression likely reflects the relative order of species-specific tissue development during ontogenesis.
authors.affiliation: Kewalo Marine Lab, PBRC/University of Hawaii, Honolulu, 96813, USA.
authors.forename: Andreas C
authors.initials: AC
authors.lastname: Fröbius
authors.forename: Elaine C
authors.initials: EC
authors.lastname: Seaver
mesh_terms: D000818:Animals; D019521:Body Patterning / Q000235:genetics; D019143:Evolution, Molecular; D015870:Gene Expression; D023061:Gene Order; D005801:Genes, Homeobox; D018398:Homeodomain Proteins / Q000032:analysis / Q000145:classification* / Q000235:genetics*; D005810:Multigene Family; D010802:Phylogeny; D011077:Polychaeta / Q000737:chemistry / Q000235:genetics / Q000254:growth & development*
chemical_list: D018398:Homeodomain Proteins