Evolution of human vision explained

THE ORIGINS of human vision evolved in the blink of an eye, according to a researcher at NUI Maynooth who tracked down the genetic history of our ability to see. The work also provides a simple explanation for how something as remarkable and complex as vision could arise.

Dr Davide Pisani led the work at Maynooth that goes a long way towards showing the shared genetic links that allowed vision to arise in so many species. The team published its findings yesterday in the prestigious US Proceedings of the National Academy of Sciences.

“We have shown there is a very simple route for going from not being able to detect light to being able to detect light,” Dr Pisani said.

The team used a supercomputer at Maynooth to compare the genomes of different species from sponges to humans. The sponge data produced by the University of California, Berkeley, helped Dr Pisani date the origins of vision back 700 million years.

The supercomputer analysis tracked back through the genetic history of a range of species until they reached a time when the sponge family was evolving away from other animals.

The researchers were looking for genes that produce opsins, the light-sensitive proteins which are key to vision. They looked at an early primitive group of organisms called placozoans. Their opsins did not change when exposed to light, but within 10 million years the next next step along the evolutionary tree – jellyfish – had evolved opsin that did react and change when exposed to light.

“In evolutionary terms, this 10 million years equates to the blink of an eye, and it shows the usefulness of the mutation that it was seized upon and became so pervasive in so much of life that we know today,” Dr Pisani said.