PUBLICATION
The evolutionary origin of nodal-related genes in teleosts
- Authors
- Fan, X., and Dougan, S.T.
- ID
- ZDB-PUB-071118-41
- Date
- 2007
- Source
- Development genes and evolution 217(11-12): 807-813 (Journal)
- Registered Authors
- Dougan, Scott T., Fan, Xiang
- Keywords
- Nodal, Squint, Cyclops, Southpaw, Evolution
- MeSH Terms
-
- Animals
- Conserved Sequence
- Embryo, Nonmammalian/cytology
- Evolution, Molecular*
- Fishes/genetics*
- Green Fluorescent Proteins/metabolism
- Nodal Protein
- Phylogeny
- Regulatory Sequences, Nucleic Acid/genetics
- Synteny
- Transforming Growth Factor beta/genetics*
- PubMed
- 17992538 Full text @ Dev. Genes Evol.
Citation
Fan, X., and Dougan, S.T. (2007) The evolutionary origin of nodal-related genes in teleosts. Development genes and evolution. 217(11-12):807-813.
Abstract
Because of an extra whole-genome duplication, zebrafish and other teleosts have two copies of genes that are present in a single copy in tetrapod genomes. Some zebrafish genes, however, are present in triplicate. For example, the nodal-related genes encode secreted proteins of the transforming growth factor beta superfamily that are required in all vertebrates to induce the mesoderm and endoderm, pattern all three germ layers, and establish the left-right axis. Zebrafish have three nodal-related genes, called ndr1/squint, ndr2/cyclops, and ndr3/southpaw. As part of an analysis of enhancer elements controlling zebrafish nodal-related gene expression, we analyzed the nodal loci in the sequenced genomes of five teleost species and four tetrapod species. Each teleost genome contains three nodal-related genes, indicating that squint, cyclops, and southpaw orthologues were present early in the teleost lineage. The genes flanking the nodal-related genes are also conserved, demonstrating a high degree of conserved synteny. Although we found little homology outside of the coding sequences in this region, pufferfish enhancer sequences work in zebrafish embryos to drive reporter gene expression in the squint expression pattern. This indicates a high degree of functional conservation of enhancer elements within the teleosts. We conclude that the ancestral squint and cyclops genes arose during the teleost-specific whole-genome duplication event and that southpaw emerged from a subsequent duplication event involving ancestral squint.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping