Sea Anemones Reveal Ancient Blueprint for Body Plans

Scientists have discovered that sea anemones, simple radial creatures, hold clues to the evolution of complex body structures. These findings could reshape our understanding of how body plans are genetically determined and passed down through generations.

Anemones’ Hidden Symmetry

Sea anemones, often appearing basic, possess a hidden front-to-back design, mirroring the organization seen in animals with heads and tails. A recent study illuminates how these soft-bodied organisms utilize chemical signals to define their “back” and “belly.”

Researchers from the **University of Vienna** investigated how sea anemones, specifically Nematostella vectensis, use a mechanism called BMP shuttling to form their bodies. This same biological process shapes the body axes in a wide range of animals, including insects and humans.

Sea anemones, known for their simple radial symmetry, actually have a hidden front-to-back body plan! A new study shows how these soft-bodied creatures use chemical signals to determine their “back” and “belly.” https://t.co/F91W5yXqj6

— Earth.com (@EarthDotCom) May 29, 2024

This discovery suggests this cellular traffic system existed over 600 million years ago. It implies it was present in a common ancestor of most modern animals. This revelation helps us understand the deep evolutionary link between simple and complex organisms. The research has the potential to unlock new insights into how body plans are encoded and inherited.

The Role of BMPs

Bone Morphogenetic Proteins (BMPs) are signals that guide developing cells. A partner molecule, Chordin, can both block these signals and move them to different locations. This movement creates precise high and low levels of BMP activity, which early cells use as a map, differentiating into various tissues and organs.

Shuttling in Action

To examine Chordin’s function, the researchers blocked its production in developing sea anemone embryos. This resulted in a halt of BMP activity and a failure to form the second body axis. Further experiments revealed that only a free-moving form of Chordin could restore BMP signaling. This showed Chordin not only blocks BMPs but also actively transports them across the developing body.

“Not all Bilateria use Chordin-mediated BMP shuttling, for example frogs do, but fish don’t, however, shuttling seems to pop up over and over again in very distantly related animals making it a good candidate for an ancestral patterning mechanism,”

—David Mörsdorf, Study’s First Author

The study, published in Science Advances, indicates the ancient nature of this mechanism. It opens new avenues for rethinking how body plans evolved in early animals. Recent data shows that the study of these body-plan development processes in the context of human birth defects is still needed (CDC, 2024).

Implications for the Future

The findings suggest a single, ancient blueprint guided the evolution of complex body shapes in many animal groups. Understanding BMP shuttling in sea anemones could aid in understanding birth defects, tissue growth, and the potential to guide stem cells. By studying these basic organisms, researchers could uncover ways to repair and regrow human body parts.