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Surgical Removal of a Complex Sensory Organ in Highly Regenerative Ctenophores
Published on: August 8, 2025
A blastoporal organizer in a ctenophore
Stanislav Kremnyov1, Tatiana Lebedeva2, Grigory Genikhovich3
1Institute of Zoology and Evolutionary Research, Faculty of Biological Sciences, Friedrich Schiller University Jena, Jena, Germany. stanislav.kremnyov@uni-jena.de.
Nature
|June 17, 2026
Summary
The blastopore lip of ctenophores exhibits organizer activity, inducing secondary body axes in transphyletic transplantation experiments. This reveals deep homology of the organizer across major animal groups, suggesting its ancestral role.
Area of Science:
- Developmental Biology
- Evolutionary Biology
- Genetics
Background:
- The dorsal blastopore lip acts as an organizer, inducing body axes in amphibians since Mangold and Spemann's 1924 experiment.
- Cnidarians also possess a blastoporal organizer, but its evolutionary origins remain unclear.
Purpose of the Study:
- To investigate the presence and function of a blastoporal organizer in ctenophores, the sister group to all other metazoans.
- To explore the evolutionary origins and deep homology of the embryonic organizer.
Main Methods:
- Transplantation of dorsal blastopore lip tissue from Mnemiopsis leidyi gastrula into host embryos.
- Transphyletic transplantation experiments using M. leidyi blastopore lip into cnidarian (Nematostella vectensis) embryos.
- Analysis of signaling pathways (β-catenin and TGFβ) required for organizer function.
Main Results:
- Transplanted M. leidyi blastopore lip induced secondary pharynx and mouth formation.
- M. leidyi blastopore lip induced a secondary body axis in N. vectensis embryos.
- Organizer function in M. leidyi depends on β-catenin and TGFβ signaling.
Conclusions:
- The blastopore lip of M. leidyi exhibits organizer activity, indicating deep homology with cnidarian and vertebrate organizers.
- The blastopore lip likely served an ancestral organizer role, crucial for the evolution of spatial cell differentiation in early metazoans.
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