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Comb Jelly Embryonic Organizer Transplanted into Sea Anemones Reveals Evolutionary Roots
6/19/2026, 1:05:08 AM
Discovery of an Embryonic Organizer in Comb Jellies
Researchers led by Stanislav Kremnyov at Friedrich Schiller University Jena identified an embryonic organizer in the comb jelly *Mnemiopsis leidyi*. Transplanting its blastopore region into embryos of the starlet sea anemone *Nematostella vectensis* induced extra mouths and pharyngeal structures. Published in *Nature* (17 June), the work shows organizer activity can function across phyla.
Historical Context of Organizer Research
The organizer concept began with Hilde Mangold’s 1920s newt cell transplants, which produced a secondary body axis and contributed to Hans Spemann’s 1935 Nobel Prize. In 2007, Ulrich Technau’s team discovered organizer-like cells in *Nematostella* embryos, prompting questions about the mechanism’s origin.
Researchers and Collaborative Team
The study was led by Stanislav Kremnyov (Friedrich Schiller University Jena) with collaborators Ulrich Technau (University of Vienna) and Andreas Hejnol (co-author, maintains a microzoo collection of invertebrates used for the experiments).
Timeline of Key Milestones
2007 Technau’s group identifies organizer cells in *Nematostella*. Kremnyov’s lab isolates the comb jelly organizer and publishes cross-phylum transplantation results in *Nature* (17 June).
Experimental Findings and Data
Comb jelly embryos are highly fecund, laying transparent embryos daily; blastopores appear hours after fertilization. Transplanted organizer tissue induced two mouths in sea anemone hosts. Morphogen release likely acts as a foreman directing cell fate.
Evolutionary Significance
If organizers existed early, they could have driven the transition to multicellularity. The findings place the organizer before the Ctenophora–Cnidaria split, reshaping animal phylogeny.
Official Statements & Responses
Kremnyov calls organizer cells a foreman that tells “the cells what they have to do and what they have to build.” Technau describes the discovery as “really exciting.” Hejnol notes that adding a comb jelly expands his microzoo’s experimental range. The authors stress further molecular work to confirm organizer universality.
Criticism & Opposition
Some scientists remain unconvinced by the claim that comb jelly organizers can function in sea anemone embryos, indicating that further evidence is needed to establish the broader applicability of organizer activity.
Conflicting Reports & Gaps
The phylogenetic placement of comb jellies is debated; many scientists place them at the base of the animal tree, while others remain unconvinced. This uncertainty makes the timing of organizer emergence unclear, requiring more comparative data.
Verbatim Quotes
- “I’m really excited to see this,” — Ulrich Technau, evolutionary developmental biologist, University of Vienna
- “They did insane things,” — Stanislav Kremnyov, developmental biologist, Friedrich Schiller University Jena
- “Until our work, it was not known when it emerged,” — Stanislav Kremnyov
- “I saw the blastopore — and what I wanted to do was just transplant it.” — Stanislav Kremnyov
Future Directions
Future work will focus on molecular characterization of the comb jelly organizer to test its universality across phyla.
