A human gene associated with hearing development has recently been involved in the establishment of other senses in sea anemones. When it comes to the sea anemone Nematostella vectens, scientists have discovered a gene known as pou-iv, or “pow-four,” that plays a critical role in the creature’s ability to perceive touch.
There’s a good chance the gene’s function in sensory formation was available in their common origin and presumably had a role in perceptual growth at the time of their ancestor’s development.
Hair cells are the hearing system’s sensory receptors in people and other species. It is the vibrations we perceive as sound that these cells detect with bunches of finger-like membrane-bound vesicles stereocilia. It is known that pou-iv is necessary for the formation of hair cells in mammals, and we understand that since deaf mice have pou-iv missing.
The tentacles of the starlet sea anemone include mechanosensory hair cells that are identical to those of the sea anemone. As a result, nothing was understood about the significance of the anemone’s pou-iv genes in sensory development.
The mutant anemones exhibited aberrant growth of the tenebrous hair cells and no sensitivity to touch when compared to the wild-type control anemones. They could not detect physical stimuli through their hair cells without pou-iv.
Anemones that had pou-iv knocked out greatly repressed a gene that is extremely similar to the polycystin 1 gene that is expressed in vertebrate, where it is essential for detecting fluid movement in kidneys. A sense of fluid flow might be a beneficial feature for aquatic organisms, even if sea anemones lack kidneys.
Overall, the findings show that pou-iv may have had a role in the evolution of mechanoreceptors cells throughout the single ancestor of Cnidaria and Bilateria. It will, however, be necessary to use information from those other phyla with older separation sites in order to track the gene back farther.
The research has been published in eLife.
