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Clonal-aggregative multicellularity tuned by salinity in a choanoflagellate
Núria Ros-Rocher1, Josean Reyes-Rivera2,3, Uzuki Horo4
1Evolutionary Cell Biology and Evolution of Morphogenesis Unit, Institut Pasteur, Université Paris-Cité, CNRS UMR3691, Paris, France. nuria.ros@pasteur.fr.
Nature
|February 25, 2026
Summary
The choanoflagellate Choanoeca flexa exhibits flexible multicellularity, forming colonies through clonal, aggregative, or combined mechanisms. This adaptability aids survival in fluctuating environments, challenging previous scientific understanding.
Area of Science:
- Evolutionary biology
- Cell biology
- Eukaryotic evolution
Background:
- Multicellularity evolved independently multiple times in eukaryotes.
- Two primary mechanisms for multicellularity are clonality and aggregation.
- These mechanisms were traditionally considered mutually exclusive.
Purpose of the Study:
- To investigate the mechanisms of multicellularity in the choanoflagellate Choanoeca flexa.
- To characterize the life history and environmental adaptability of C. flexa.
- To challenge existing generalizations about choanoflagellate multicellularity.
Main Methods:
- Field observations in natural habitats (ephemeral splash pools).
- Characterization of C. flexa life history and colony formation.
- Analysis of clonal and aggregative multicellularity mechanisms.
Main Results:
- Choanoeca flexa forms motile and contractile cell sheets via clonal, aggregative, or combined processes.
- C. flexa exhibits reversible transitions between unicellularity and multicellularity.
- Kin recognition influences aggregation, constraining inter-strain interactions.
Conclusions:
- Clonal-aggregative multicellularity is a versatile strategy for C. flexa in variable environments.
- Findings expand the known range of multicellularity strategies in choanozoans.
- The study challenges prior assumptions about choanoflagellate multicellularity.
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