PUBLICATION

Developmental genetic mechanisms of evolutionary tooth loss in cypriniform fishes

Authors

Stock, D.W., Jackman, W.R., and Trapani, J.

ID

ZDB-PUB-060719-16

Date

2006

Source

Development (Cambridge, England) 133(16): 3127-3137 (Journal)

Registered Authors

Jackman, William (Bill), Stock, David W.

Keywords

Zebrafish, Astyanax, Medaka, Catfish, Dlx, Fgf, Constraint

MeSH Terms

Epithelium/metabolism
Biological Evolution*
Mouth Mucosa/metabolism
Tooth Loss/genetics*
Transcription Factors/genetics
Transcription Factors/metabolism
PAX9 Transcription Factor/genetics
PAX9 Transcription Factor/metabolism
Amino Acid Sequence
Homeodomain Proteins/genetics
Homeodomain Proteins/metabolism
Signal Transduction
Zebrafish/genetics
Zebrafish/growth & development*
Cypriniformes/genetics*
Cypriniformes/growth & development*
Animals
Fibroblast Growth Factors/antagonists & inhibitors
Fibroblast Growth Factors/metabolism
Molecular Sequence Data

(all 20)

PubMed

16831836 Full text @ Development

Abstract

The fossil record indicates that cypriniform fishes, a group including the zebrafish, lost oral teeth over 50 million years ago. Despite subsequent diversification of feeding modes, no cypriniform has regained oral teeth, suggesting the zebrafish as a model for studying the developmental genetic basis of evolutionary constraint. To investigate the mechanism of cypriniform tooth loss, we compared the oral expression of seven genes whose mammalian orthologs are involved in tooth initiation in the zebrafish and the Mexican tetra, Astyanax mexicanus, a related species retaining oral teeth. The most significant difference we found was an absence in zebrafish oral epithelium of expression of dlx2a and dlx2b, transcription factors that are expressed in early Astyanax odontogenic epithelium. Analysis of orthologous genes in the Japanese medaka (Oryzias latipes) and a catfish (Synodontis multipunctatus) suggests that expression was lost in cypriniforms, rather than gained in Astyanax. Treatment of Astyanax with an inhibitor of Fibroblast growth factor (Fgf) signaling produced a partial phenocopy of the zebrafish oral region, in that oral teeth, and expression of dlx2a and dlx2b, were lost, whereas shh and pitx2, genes whose expression is present in zebrafish oral epithelium, were unaffected. We hypothesize that a loss of Fgf signaling to oral epithelium was associated with cypriniform tooth loss.

Genes / Markers

Figures

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Expression

Gene	Fish	Conditions	Stage	Qualifier	Anatomy	Assay	Figure
dlx2a	WT	standard conditions	Day 5		forebrain	ISH	Fig. 4
dlx2a	WT	standard conditions	Protruding-mouth		forebrain	ISH	Fig. 4
dlx2a	WT	standard conditions	Pec-fin		forebrain	ISH	Fig. 4
dlx2a	WT	control	Long-pec		head mesenchyme	ISH	Fig. 7
dlx2a	WT	chemical treatment: SU5402	Long-pec	Not Detected	head mesenchyme	ISH	Fig. 7
dlx2a	WT	standard conditions	Pec-fin		mandibular arch skeleton	ISH	Fig. 4
dlx2a	WT	standard conditions	Day 5		mandibular arch skeleton	ISH	Fig. 4
dlx2a	WT	standard conditions	Protruding-mouth		mandibular arch skeleton	ISH	Fig. 4
dlx2a	WT	standard conditions	Protruding-mouth	Not Detected	oral epithelium	ISH	Fig. 4
dlx2a	WT	standard conditions	Day 5	Not Detected	oral epithelium	ISH	Fig. 4

1 - 10 of 26

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Phenotype

Mutations / Transgenics

Human Disease / Model

Sequence Targeting Reagents

Fish

Fish
WT

Antibodies

Orthology

Engineered Foreign Genes

Mapping

Stock et al., 2006 ZDB-PUB-060719-16 PMID:16831836

Developmental genetic mechanisms of evolutionary tooth loss in cypriniform fishes

Stock et al., 2006

ZDB-PUB-060719-16
PMID:16831836