Patrick, is that you? Scientists make bizarre discovery about sea stars

Recently, a study published in the magazine Nature unraveled an enigma that has intrigued the scientific community for a long time: the location of the “head” of sea stars.

In fact, through the use of genetics and molecular biology tools, the research group mapped body regions, resulting in the creation of a three-dimensional atlas that reveals the genetic expression of sea stars.

The answer to this question, however, turned out to be more complex than initially imagined. The study authors came to the conclusion that the “head” of a starfish is not found in a specific location.

Contrary to what was thought, regions analogous to the head are distributed both in the center of the sea star’s body and in the center of each of its limbs.

Multiple heads??? Like this?!

Sea stars belong to the class of animals called echinoderms. In order to unravel the enigma related to the body organization of these creatures, scientists investigated their development process, using advanced molecular biology techniques.

In this context, molecular markers were applied and served as a guide to map the body plan of each organism. This allowed the precise identification of the location of each cell in the organism’s body.

Image: shutterstock/Vojce

The researchers commented on this approach, stating:

“If you take the skin off an animal and look at the genes involved in defining the head and tail, the same genes code for these body regions in all groups of animals. So we ignore the anatomy and ask: is there a molecular axis hidden beneath all this strange anatomy and what is its role in a starfish forming a pentaradial body plan?”

The research revealed that sea stars have a “head”-like region in the center of each of their “arms” and a “tail”-like region along the perimeter.

Scientists expressed satisfaction with the discovery, highlighting that even in the most recent molecular research, there were uncertainties in the echinoderm evolutionary tree. The revelation of this new molecular aspect contributes to completing the puzzle.

It is important to highlight that, although there is kinship between echinoderms and humans, the life cycle and anatomy of echinoderms starfish differ substantially from ours.

Finally, the life cycle of these animals begins with the fertilized egg phase. These later hatch into larvae that remain adrift in the ocean in the form of plankton, for a period that can last weeks or even months.

Eventually, these larvae find their way to the bottom of the ocean, where they undergo a metamorphosis that takes them from the initially bilateral body structure to the iconic five-pointed adult form characteristic of sea stars.