Amphioxus Postembryonic Development Reveals the Homology of Chordate Metamorphosis

Mathilde Paris, Hector Escriva, Michael Schubert, Frédéric Brunet, Julius Brtko, Fabrice Ciesielski, Dominique Roecklin, Valérie Vivat-Hannah, Emilien L. Jamin, Jean Pierre Cravedi, Thomas S. Scanlan, Jean Paul Renaud, Nicholas D. Holland, Vincent Laudet

Research output: Contribution to journalArticlepeer-review

113 Scopus citations


Most studies in evolution are centered on how homologous genes, structures, and/or processes appeared and diverged. Although historical homology is well defined as a concept, in practice its establishment can be problematic, especially for some morphological traits or developmental processes. Metamorphosis in chordates is such an enigmatic character. Defined as a spectacular postembryonic larva-to-adult transition, it shows a wide morphological diversity between the different chordate lineages, suggesting that it might have appeared several times independently. In vertebrates, metamorphosis is triggered by binding of the thyroid hormones (THs) T4 and T3 to thyroid-hormone receptors (TRs). Here we show that a TH derivative, triiodothyroacetic acid (TRIAC), induces metamorphosis in the cephalochordate amphioxus. The amphioxus TR (amphiTR) mediates spontaneous and TRIAC-induced metamorphosis because it strongly binds to TRIAC, and a specific TR antagonist, NH3, inhibits both spontaneous and TRIAC-induced metamorphosis. Moreover, as in amphibians, amphiTR expression levels increase around metamorphosis and are enhanced by THs. Therefore, TH-regulated metamorphosis, mediated by TR, is an ancestral feature of all chordates. This conservation of a regulatory network supports the homology of metamorphosis in the chordate lineage.

Original languageEnglish (US)
Pages (from-to)825-830
Number of pages6
JournalCurrent Biology
Issue number11
StatePublished - Jun 3 2008



ASJC Scopus subject areas

  • General Biochemistry, Genetics and Molecular Biology
  • General Agricultural and Biological Sciences


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