A tiny ocean worm has just provided scientists with new information about how eyes evolve. Research on the marine bristleworm platynereis shows that its eye countries grow throughout its adult life, driven by neural stem cells that respond to light. This process is surprisingly similar to vertebrate eye development.
Research at the University of Vienna and the Alfred Wegener Institute highlights important similarities between the eye growth process of platynereis dumerilii and those of vertebrates.
In the article, A Worm’s Surprising Secret Might Hold The Key to Eye Evolution, a line reads, “In a groundbreaking finding, the scientists showed that these marine worms have a neural stem cell region, akin to the ciliary marginal zone in vertebrate eyes, which enables the continuous expansion of their eyes. Crucially, the research suggests that environmental light regulates this process, potentially altering the way we understand how sensory organs evolve,” (PAR 2).
The study was published in Nature Communications, and it provides new explanations and perspectives on eye evolution. It also highlights how light can influence the adult nervous system, even in species viewed as “biologically simple.”
Scientists have long wondered how these invertebrate eyes continue growing during adulthood. These studies have answered some of those questions.
“It was remarkable to find dividing cells at the edge of the worm’s retina—the same place where some groups of vertebrates maintain their retinal stem cells for life-long eye growth,” said Nadja Milivojev, first author of the study and researcher at the University of Vienna’s Department of Neurosciences and Developmental Biology.
The findings challenged assumptions about which animals have “sophisticated visual systems.” When people imagine creatures with complex eyes, they think of mammals, birds, or marine life, like octopi and squids. However, these bristle worms possess camera-type eyes that are capable of surprisingly high resolution value.
From the article Marine Worm Eyes Reveal Surprising Secrets About How Vision Evolved: “Camera-type eyes, which feature a lens that focuses light onto a retina, have long served as textbook examples of convergent evolution—the phenomenon where unrelated species independently develop similar structures to solve the same biological problem. For nearly 140 years, the comparison between cephalopod and vertebrate eyes has dominated discussions of this evolutionary principle. The new research expands this conversation by demonstrating that annelid worms deserve a place in that discussion,” (PAR 5).
These discoveries are more than just academic curiosity; understanding these shared mechanisms within our eyes could help the medical research into human eye diseases and potential therapies. This offers hope that creatures, like marine worms, might one day light the path towards restoring human vision.
