Divergent mechanisms regulate conserved cardiopharyngeal development and gene expression in distantly related ascidians

Alberto Stolfi, Elijah K. Lowe, Claudia Racioppi, Filomena Ristoratore, Charles Brown, Billie J. Swalla, Lionel Christiaen

Research output: Contribution to journalArticlepeer-review

54 Scopus citations


Ascidians present a striking dichotomy between conserved phenotypes and divergent genomes: embryonic cell lineages and gene expression patterns are conserved between distantly related species. Much research has focused on Ciona or Halocynthia spp. but development in other ascidians remains poorly characterized. In this study, we surveyed the multipotent myogenic B7.5 lineage in Molgula spp. Comparisons to the homologous lineage in Ciona revealed identical cell division and fate specification events that result in segregation of larval, cardiac, and pharyngeal muscle progenitors. Moreover, the expression patterns of key regulators are conserved, but cross-species transgenic assays uncovered incompatibility, or 'unintelligibility', of orthologous cis-regulatory sequences between Molgula and Ciona. These sequences drive identical expression patterns that are not recapitulated in cross-species assays. We show that this unintelligibility is likely due to changes in both cis- and trans-acting elements, hinting at widespread and frequent turnover of regulatory mechanisms underlying otherwise conserved aspects of ascidian embryogenesis.

Original languageEnglish (US)
Pages (from-to)e03728
StatePublished - Jan 1 2014
Externally publishedYes


  • ascidians
  • cardiopharyngeal mesoderm
  • development
  • developmental biology
  • DSD
  • evolution
  • evolutionary biology
  • genomics
  • stem cells
  • tunicates

ASJC Scopus subject areas

  • Neuroscience(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)


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