@article{fdi:010048502,
  title = {{A}re {H}ox genes ancestrally involved in axial patterning ? {E}vidence from the hydrozoan {C}lytia hemisphaerica ({C}nidaria)},
  author = {{C}hiori, {R}. and {J}ager, {M}. and {D}enker, {E}. and {W}incker, {P}. and {D}a {S}ilva, {C}. and {L}e {G}uyader, {H}erv{\'e} and {M}anuel, {M}. and {Q}ueinnec, {E}.},
  editor = {},
  language = {{ENG}},
  abstract = {{B}ackground: {T}he early evolution and diversification of {H}ox-related genes in eumetazoans has been the subject of conflicting hypotheses concerning the evolutionary conservation of their role in axial patterning and the pre-bilaterian origin of the {H}ox and {P}ara{H}ox clusters. {T}he diversification of {H}ox/{P}ara{H}ox genes clearly predates the origin of bilaterians. {H}owever, the existence of a "{H}ox code' predating the cnidarian-bilaterian ancestor and supporting the deep homology of axes is more controversial. {T}his assumption was mainly based on the interpretation of {H}ox expression data from the sea anemone, but growing evidence from other cnidarian taxa puts into question this hypothesis. {M}ethodology/{P}rincipal {F}indings: {H}ox, {P}ara{H}ox and {H}ox-related genes have been investigated here by phylogenetic analysis and in situ hybridisation in {C}lytia hemisphaerica, an hydrozoan species with medusa and polyp stages alternating in the life cycle. {O}ur phylogenetic analyses do not support an origin of {P}ara{H}ox and {H}ox genes by duplication of an ancestral {P}roto{H}ox cluster, and reveal a diversification of the cnidarian {HOX}9-14 genes into three groups called {A}, {B}, {C}. {A}mong the 7 examined genes, only those belonging to the {HOX}9-14 and the {CDX} groups exhibit a restricted expression along the oralaboral axis during development and in the planula larva, while the others are expressed in very specialised areas at the medusa stage. {C}onclusions/{S}ignificance: {C}ross species comparison reveals a strong variability of gene expression along the oral-aboral axis and during the life cycle among cnidarian lineages. {T}he most parsimonious interpretation is that the {H}ox code, collinearity and conservative role along the antero-posterior axis are bilaterian innovations.},
  keywords = {},
  booktitle = {},
  journal = {{P}los {O}ne},
  volume = {4},
  numero = {1},
  pages = {e4231},
  ISSN = {1932-6203},
  year = {2009},
  DOI = {10.1371/journal.pone.0004231},
  URL = {https://www.documentation.ird.fr/hor/fdi:010048502},
}