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Ancient linkage of a POU class 6 and an anterior hox‐like gene in cnidaria: implications for the evolution of homeobox genes
Author(s) -
Kamm Kai,
Schierwater Bernd
Publication year - 2007
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.21196
Subject(s) - homeobox , hox gene , pou domain , biology , homeobox a1 , homeobox protein nkx 2.5 , genetics , gene , hnf1b , emx2 , evolutionary biology , transcription factor
Linkage analyses in metazoan genomes suggest two ancestral arrays for the majority of homeobox genes. The related homeobox genes and chromosomal regions that are dispersed in extant species derived possibly from only two single common ancestor regions. One proposed ancestral array, designated as ANTP mega‐array, contains most of the ANTP class homeobox genes; the second, named the contraHox super‐paralogon, would consist of the classes PRD, POU, LIM, CUT, prospero, TALE and SIX. Here, we report the tight linkage of a POU class 6 gene to an anterior Hox‐like gene in the hydrozoan Eleutheria dichotoma and discuss its possible significance for the evolution of homeobox genes. POU class 6 genes also seem to be ancestrally linked to the HoxC and A clusters in vertebrates, despite POU homeobox genes belonging to the contraHox paralogon. Hence, the much tighter linkage of a POU class 6 gene to an anterior Hox‐like gene in a cnidarian is possibly the evolutionary echo of an ancestral genomic region from which most metazoan homeobox classes emerged. J. Exp. Zool. (Mol. Dev. Evol.) 308B:777–784, 2007 . © 2007 Wiley‐Liss, Inc.