London, Jan 30 (IANS): Scientists from the University of Southampton have discovered the genetic basis which allows corals to produce their stunning range of colours.

They have found that instead of using a single gene to control pigment production, corals use multiple copies of the same gene.

Depending on how many genes are active, the corals will become more or less colourful.

"The key finding is that these so-called 'colour morphs' do not use just one single gene to control the pigment production, but multiple identical copies thereof," explained Jorg Wiedenmann, professor of biological oceanography.

The research also explained how this strategy could help corals to survive in stressful environments.

Using the staghorn coral Acropora millepora as a model, the team found that the fluorescent pigments that are mostly responsible for coral colours act as sunscreens for the symbiotic algae that live in the coral tissue.

Corals are firmly attached to the substrata so they cannot just move in the shade when they receive too much sunlight.

Instead, they need to boost their capacity to cope with too much sun during these times.

"We show that increased light levels switch the genes on that are responsible for the production of the colourful sunscreening pigments.

This is why corals are usually more colourful in the most light exposed colony parts," Wiedenmann informed.

The finding that appeared in the journal Molecular Biology suggests that the repertoire of reef corals' stress responses is larger than previously thought.