Scientists discover unicellular organism that sheds light on evolution of animal multicellularity
Researchers studying the marine microorganism Ministeria vibrans found that it forms stable aggregates and deploys genetic homologs of animal multicellularity genes during this process. The study, published in Nature, adds to growing evidence that aggregation — long dismissed as a path to complex multicellularity — may have been a key evolutionary stepping stone for animals. The findings suggest that the genetic toolkit underlying animal multicellular development may have originated in unicellular ancestors that used these genes for aggregation.
A new study published in Nature by researchers from Indiana University Bloomington, Uppsala University, and the Institute of Evolutionary Biology in Barcelona reports that Ministeria vibrans, a marine free-living unicellular relative of animals, forms homogeneous aggregates with reproducible kinetics and long-term stability. The researchers found that homologs of many animal genes involved in cell adhesion, signaling, and transcriptional regulation are actively deployed during this aggregation process. Improved feeding and mating are proposed as likely evolutionary drivers of the behavior. The discovery is significant because aggregation has historically been dismissed as a route to complex multicellularity, yet this study — combined with prior findings in choanoflagellates and the filasterean Capsaspora owczarzaki — suggests aggregation is widespread among close unicellular relatives of animals. The authors argue that these genes may have originally evolved to support aggregation in unicellular ancestors before being co-opted into the developmental programs of the first true animals. The work implies that aggregative multicellularity was central to assembling the genetic toolkit that made animal life possible.
Limitations & open questions
The study is described as an unedited early-access manuscript and has not yet undergone final editorial review, meaning errors may be present. Key open questions include how the specific molecular mechanisms by which these gene homologs function in aggregation compare to their roles in animal development.
What different sources said
- Nature NewsCenter
A unicellular relative links aggregative multicellularity to animal origins
- Phys.orgCenter
Why cells started sticking together could help explain how animals first evolved
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