According to a paper published in the journal PLOS Genetics, humans got the ability to see colors from gorillas and chimpanzees in the evolution process.
After two decades of research, scientists have finished a detailed and complete picture of the evolution of human color vision.
Around 90 million years ago, our primitive mammalian ancestors were nocturnal and had UV-sensitive and red-sensitive color. This gave them a bi-chromatic view of the world.
Around 30 million years ago, they evolved four classes of opsin genes, which gave them the ability to see the full-color spectrum of visible light, except for UV.
According to lead author of the study Shozo Yokoyama, the research team traced all of the evolutionary pathways, going back 90 million years that led to human color vision.
To fully understand how these changes are generated, it was necessary to evaluate the relationship between genes and functions. Therefore, the researchers focused on the seven genetic mutations involved in losing UV vision and tried to achieve the current function of a blue-sensitive pigment.
The blue-sensitive visual pigment in human evolved from the UV-sensitive pigment in the ancient ancestor by seven mutations.
There are 5,040 possible evolutionary paths connecting them. The research team identified the possible pathways for the amino acid changes required to bring about the genetic changes.
The team experimentally examined the genetic composition and color perception for every one of these 5,040 possibilities.
Yokoyama said, “We found that of the seven genetic changes required, each of them individually has no effect. It is only when several of the changes combine in a particular order that the evolutionary pathway can be completed”.
In other words, an animal’s external environment drives natural selection, so do changes in the animal’s molecular environment.