March 19, 2009

Study finds elephant sharks perceive color

Singaporean and British scientists say they used genome sequencing to discover the elephant shark can see colors much in the same way humans can.

Byrappa Venkatesh of Singapore's Institute of Molecular and Cell Biology, and Professor David Hunt of the University College London's Institute of Ophthalmology said the finding might enhance scientists' understanding of how color vision evolved in early vertebrates during the past 450 million years.

The elephant shark is a primitive deep-sea fish that belongs to the oldest living family of jawed vertebrates.

It was unexpected that a 'primitive' vertebrate like the elephant shark had the potential for color vision like humans. The discovery shows that it has acquired the traits for color vision during evolution in parallel with humans, said Venkatesh, who led the research that appears in the journal Genome Research.

In a separate paper, published in the journal Molecular Biology and Evolution, the research team said they also discovered the protein sequences in elephant sharks were evolving at a slower rate than in other vertebrates.

That finding, said the scientists, suggests the elephant shark has retained more features of the ancestral genome than other vertebrates belonging to the same evolutionary tree and hence is a useful model for gaining insight into the ancestral genome, in which the human genome also has its roots.