Human eyes and squid eyes have the same evolutionary process

Evolution has created amazing changes. There are traits that have evolved many times in different species. The flying ancestors of birds and the ancestors of bat mammals all evolved their wings independently, an example of convergent evolution.

A similar example is the eyes of humans and squid. A new study shows that, despite being completely different species, both humans and squid undergo the same evolutionary eye process.

Like all other organs of the body, the eye is the product of the activity of many different genes. Most of these genes carry information that regulates the formation of eye parts. For example, a gene is responsible for forming light-sensitive pigments in the eye, while another gene is responsible for the formation of the lens.

Besides the genes that make up the parts of the eye, some genes are responsible for the structure of the eye. Instead of carrying the information to make up the parts of the eye, these genes carry information that specifies the location and timing of eye parts that need to be assembled and assembled. Because of its role in controlling the process of eye formation, these genes are called control genes .

The most important gene among the control genes is called Pax6. Ancient Pax6 gene is likely to help form the earliest form of the eye - a collection of light-sensing cells that work together to inform a primitive creature that it is in the light, dark place. or where there is shade.

Today, traces of Pax6 gene are found in many different organisms, from birds and bees to shellfish and whales, even in squid and human species. This means that the Pax6 gene has been present even before the evolution of different species in the Cambrian period 500 million years ago.

Pax6 gene has regulated the formation of various types of eyes. From the simple eye, it helps insects evolve double-eyed forms using a variety of light-sensing components to recognize images.

This gene also helps form the human eye as well as other vertebrate relatives, the camera eye, a closed structure with iris and vitreous lenses, intraocular translation and visual recognition retina.

In order to create such a complex structure, the activities that Pax6 controls also become very complicated. In order to complete the task, evolution has increased the number of information in a single Pax6 gene.

Like other genes, the Pax6 gene is also written in DNA code. To work, DNA needs to be read and copied to another type of code called RNA.

Photo: Live Science

RNA code is interesting in that it can be edited. One way to edit it is to cut the segment, ie remove part of the middle of the code and connect the other two parts together.

The great thing about cutting is from a piece where RNA can create two different types of information. The RNA code of the Pax6 gene may also be cut in the same way.

In a recent study, Atsushi Ogura and colleagues at Nagahama Biological Science and Technology Institute found that cutting Pax6 RNA was used in the process of forming camera eyes in species like squid and octopus. , molluscs.

The eyes of these animals have characteristics like vertebrate eyes.

The common ancestor of molluscs and vertebrates has existed more than 500 million years ago.

Cutting RNA fragments of the Pax6 gene in mollusks is a great example of how evolution is offering a similar solution in many different ways. Using similar structures, evolution has created remarkable innovations.