Sea stars reveal how simple tubes become complex organs | Earth

A new study has revealed that sea stars can build the same organ in remarkably different ways.

Although three species all ended up with an identical internal structure, each followed its own developmental path to get there.

By watching the organ form in transparent sea star larvae, researchers found that evolution can arrive at the same destination through multiple routes.

The findings shed new light on one of developmental biology’s enduring questions, whether organs must follow a single blueprint or can reach the same final form in different ways.

The discovery could have implications beyond sea stars. Like many human organs, including the heart, lungs, and kidneys, the sea star organ begins as a simple tube.

This makes it a useful model for understanding how complex organs take shape during development.

The work comes from the lab of Margherita Perillo at the Marine Biological Laboratory (MBL) in Woods Hole, Massachusetts.

Her team followed the Forbes’ sea star, Asterias forbesi, a keystone predator of the North Atlantic, from egg to young adult.

This is the first detailed record of its development despite more than 70 years of study. Part of the reason Forbes’ sea stars are studied so closely is disease.