title: The evolution of the vertebrate Dlx gene family.
abstract: The vertebrate Dlx gene family consists of homeobox-containing transcription factors distributed in pairs on the same chromosomes as the Hox genes. To investigate the evolutionary history of Dlx genes, we have cloned five new zebrafish family members and have provided additional sequence information for two mouse genes. Phylogenetic analyses of Dlx gene sequences considered in the context of their chromosomal arrangements suggest that an initial tandem duplication produced a linked pair of Dlx genes after the divergence of chordates and arthropods but prior to the divergence of tunicates and vertebrates. This pair of Dlx genes was then duplicated in the chromosomal events that led to the four clusters of Hox genes characteristic of bony fish and tetrapods. It is possible that a pair of Dlx genes linked to the Hoxc cluster has been lost from mammals. We were unable to distinguish between independent duplication and retention of the ancestral state of bony vertebrates to explain the presence of a greater number of Dlx genes in zebrafish than mammals. Determination of the linkage relationship of these additional zebrafish Dlx genes to Hox clusters should help resolve this issue.
authors.affiliation: Department of Anthropology, Pennsylvania State University, University Park 16802, USA.
authors.forename: D W
authors.initials: DW
authors.lastname: Stock
authors.forename: D L
authors.initials: DL
authors.lastname: Ellies
authors.forename: Z
authors.initials: Z
authors.lastname: Zhao
authors.forename: M
authors.initials: M
authors.lastname: Ekker
authors.forename: F H
authors.initials: FH
authors.lastname: Ruddle
authors.forename: K M
authors.initials: KM
authors.lastname: Weiss
mesh_terms: D000818:Animals; D001483:Base Sequence; D005075:Biological Evolution; D003001:Cloning, Molecular; D003598:Cytoskeletal Proteins; D004268:DNA-Binding Proteins / Q000235:genetics*; D015870:Gene Expression; D005801:Genes, Homeobox; D008040:Genetic Linkage; D018398:Homeodomain Proteins / Q000235:genetics*; D051379:Mice / Q000235:genetics*; D008969:Molecular Sequence Data; D005810:Multigene Family; D010802:Phylogeny; D016601:RNA-Binding Proteins; D017386:Sequence Homology, Amino Acid; D009626:Terminology as Topic; D014157:Transcription Factors / Q000235:genetics*; D015027:Zebrafish / Q000235:genetics*; D029961:Zebrafish Proteins
chemical_list: D003598:Cytoskeletal Proteins; D004268:DNA-Binding Proteins; C088334:Distal-less homeobox proteins; C501120:Dlx5 protein, mouse; C100597:Dlx6 protein, mouse; D018398:Homeodomain Proteins; D016601:RNA-Binding Proteins; C093661:Tes protein, mouse; D014157:Transcription Factors; D029961:Zebrafish Proteins; C501122:dlx5a protein, zebrafish; C491015:dlx6a protein, zebrafish