Saturday, March 13, 2010

Seeing the 600,000,000 Year Old Origins of Vision

There are many genes involved in vision, and there is an ion-channel gene (opsin) responsible for starting the neural impulse of vision. This gene controls the entrance and exit of ions and thus, acts as a gateway. "We determined which genetic 'gateway,' or ion channel, in hydra is involved in light sensitivity," said senior author Prof. Todd H. Oakley of UCSB's Department of Ecology, Evolution and Marine Biology. "This is the same gateway that is used in human vision."

Hydra are simple animals belonging to the phylum cnidaria, which first emerged 600 million years ago. The vision of insects emerged later than the visual machinery found in hydra and vertebrate animals.

"This work continues to challenge the misunderstanding that evolution represents a ladder-like march of progress, with humans at the pinnacle," said Oakley. "Instead, it illustrates how all organisms—humans included—are a complex mix of ancient and new characteristics."

[Source: physorg.com]