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Miniature of Wnt Signaling is Dispensable to Formation of the First Tooth in <i>D. Rerio</i>
Wnt Signaling is Dispensable to Formation of the First Tooth in D. Rerio
This record is embargoed.
    • Embargo End Date: 2025-05-14

    Date: 2020-01-01

    Creator: Zachary C. LeBlanc

    Access: Embargoed

      Miniature of An analysis and characterization of Sonic Hedgehog and Fgf genes in <i>Danio rerio</i> embryonic tooth development
      An analysis and characterization of Sonic Hedgehog and Fgf genes in Danio rerio embryonic tooth development
      This record is embargoed.
        • Embargo End Date: 2027-05-18

        Date: 2022-01-01

        Creator: Lauren Kanoelani Waters

        Access: Embargoed

          Miniature of Developmental genetic mechanisms of evolutionary tooth loss in cypriniform fishes
          Developmental genetic mechanisms of evolutionary tooth loss in cypriniform fishes

          Date: 2006-08-01

          Creator: David W. Stock, William R. Jackman, Josh Trapani

          Access: Open access

          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 Astyanaxwith an inhibitor of Fibroblast growth factor (Fgf) signaling produced a partial phenocopy of the zebrafish oral region, in that oral teeth, and expression of d1x2a and d1x2b, 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.