Study Uncovers Facts About Evolution Of Eye

Eyes are exquisitely complicated organs. Eyes play the role of a camera that focuses on light and coverts it into an electrical signal that the brain translates into images. But in this, the key to vision is the light sensitive protein known as Opsins.

According to a new study from the National University of Ireland, Maynooth, and the University of Bristol,  Opsins may have evolved earlier and undergone fewer genetic changes than previously believed.

The study used computer modeling to explain in detail.  It was used to shed light on the origin of sight in animals including humans.

Prior to this, there were several studies done that debated on the evolutionary origin of vision but failed to provide substantial results due to inconsistent reports of phylogenetic relationships among the earliest Opsin-possessing animals.

This study was done by Dr. Davide  Pisani of Bristol's School of Earth Sciences and colleagues at NUI, Maynooth. For the study they did a computational analysis to test every hypothesis of Opsin evolution proposed till date. 

They incorporated all crucial elements such as available genomic information from all relevant animal lineages, including a newly sequenced group of sponges and the Cnidarians, a group of animals believed to possess the world's earliest eyes.

With the help of this information they framed a timeline with an Opsin ancestor common to all groups that existed some 700 million years ago.

The study revealed that the Opsin that was considered blind underwent key genetic changes over the span of 11 million years and evolved with the ability to detect light.

Dr Pisani said: "The great relevance of our study is that we traced the earliest origin of vision and we found that it originated only once in animals. This is an astonishing discovery because it implies that our study uncovered, in consequence, how and when vision evolved in humans."

This study was published in the Oct. 29 Proceedings of National Academy of Sciences (PNAS).