14 DAY TRIAL // A team of investigators in the United States believes it may have discovered the primitive precursor of the human eye, in the embryo of a type of marine invertebrate called a brachiopod.
What the group discovered was a series of light-detecting cells, or photoreceptors, whose organization is apparently very similar to the early human eye. This may hint at a common and distant origin.
The investigation was conducted by researchers with the University of Hawaii Kewalo Marine Laboratory, in Honolulu, who were led by expert Dr. Yale Passamaneck.
For quite some time, scientists have been proposing that the human eye had a rather humble origin, starting out as a simple patch of cells on the surface of some primordial animal.
Over millions of years, the structure became increasingly complex through the addition of improved features. Some of these may have included the formation of a neural connection to the brain, the appearance of pigmentation, as well as the development of a lens.
But studies conducted thus far have identified very few of the steps that led to the evolution of the human eye. This organ is arguably one of the most complex and intricate in the human body, and its mechanism of operations is fascinating.
“This research provides a new model for understanding the very earliest stages of eye evolution, how simple cells on the surface of an animal could become able to respond to light,” Passamaneck says.
The study also provides additional insight into “how these simple cells could be connected to eventually form something as complex as the human eye,” the team leader goes on to say.
In the recent experiments, the scientists analyzed brachiopod embryos and discovered two distinct groups of light-detecting cells that may look similar to precursors of the human eye as well.
The team found that the embryos contain ciliary photoreceptors, one of the two types of photoreceptors that can be found in the human eye as well, Daily Galaxy reports.
According to the scientists, the organization of these cellular patches is tremendously similar to the way past studies hypothesized the early human eye would have looked like.
Interestingly, it was also discovered that the ciliary photoreceptors on the invertebrates developed ahead of any neurons in their nerve system. This was discovered by analyzing the expression of genes responsible for the development of light-detecting cells.