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Ancient complexity of the non‐Hox ANTP gene complement in the anthozoan Nematostella vectensis . Implications for the evolution of the ANTP superclass
Author(s) -
Kamm Kai,
Schierwater Bernd
Publication year - 2006
Publication title -
journal of experimental zoology part b: molecular and developmental evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.823
H-Index - 63
eISSN - 1552-5015
pISSN - 1552-5007
DOI - 10.1002/jez.b.21123
Subject(s) - hox gene , antennapedia , homeobox , biology , genome , gene , bilateria , genetics , evolutionary biology , phylogenetics , transcription factor
The origin and evolution of ANTP superclass genes has raised controversial discussions. While recent evidence suggests that a true Hox cluster emerged after the cnidarian bilaterian split, the origin of the ANTP superclass as a whole remains unclear. Based on analyses of bilaterian genomes, it seems very likely that clustering has once been a characteristic of all ANTP homeobox genes and that their ancestors have emerged through several series of cis ‐duplications from the same genomic region. Since the diploblastic Cnidaria possess orthologs of some non‐Hox ANTP genes, at least some steps of the expansion of this hypothetical homeobox gene array must have occurred in the last common ancestor of both lineages—but it is unknown to what extent. By screening the unassembled Nematostella genome, we have identified unambiguous orthologs to almost all non‐Hox ANTP genes which are present in Bilateria—with the exception of En, Tlx and (possibly) Vax. Furthermore, Nematostella possesses ANTP genes that are missing in some bilaterian lineages, like the rough gene or NK7. In addition, several ANTP homeobox gene families have been independently duplicated in Nematostella . We conclude that the last cnidarian/bilaterian ancestor already harboured the almost full complement of non‐Hox ANTP genes before the Hox system evolved. J. Exp. Zool. (Mol. Dev. Evol.) 306B, 2006 . © 2006 Wiley‐Liss, Inc.