Sea anemones and humans share a 600-million-year-old evolutionary secret

A recent study reveals that sea anemones and humans may share a far older evolutionary link than previously thought. Researchers at the University of Vienna found that these simple marine creatures use body-building techniques once believed unique to more complex animals, including humans. The findings suggest a common ancestor with bilateral symmetry existed over 600 million years ago.

The study, published in Science Advances, focused on how sea anemones construct their bodies. Scientists discovered that these cnidarians employ BMP shuttling—a process where proteins like Chordin transport bone morphogenetic proteins (BMP) to create concentration gradients. These gradients signal where different tissues and organs should form, much like in bilaterians such as flies, frogs, and humans.

Lead author David Möersdorf proposed that BMP shuttling could be an ancestral mechanism for body patterning in animals. The team observed that Chordin, an inhibitor, functions as a BMP shuttle in sea anemones, mirroring its role in bilaterians. This similarity hints that the trait predates the evolutionary split between cnidarians and bilaterians.

Further research on anthozoans (sea anemones and sea fans) and hydra reinforced these findings. In hydra, BMP signalling controls tentacle and foot development, with inhibition promoting foot growth while encouraging tentacle formation. Both groups rely on conserved extracellular modulators like Chordin and Gremlin—proteins also found in cnidarian development.

Senior author Grigory Genikhovich acknowledged that independent evolution remains possible. However, the shared use of Chordin in both lineages strongly suggests a bilateral ancestor. If confirmed, this would push back the origins of complex body-planning mechanisms by hundreds of millions of years.

The discovery challenges long-held assumptions about when and how bilateral body plans first emerged. By showing that sea anemones and humans share fundamental developmental processes, the study provides new clues about early animal evolution. Future research may further clarify how these ancient mechanisms shaped the diversity of life seen today.