Sydney, Aug 7 - Casting a perfectly rounded pearl will now be possible, thanks to the most comprehensive sequencing of the oyster genome in a new project.

The ultimate aim of the project is to identify the genes responsible for characteristics of a pearl, such as colour, shape and lustre. Pearl farmers will then only grow oysters with that gene sequence.

Once these genes have been identified, it will allow oysters that have the right combination of genes to be selectively bred to produce the pearls of the highest quality.

Project leader and aqua-culturist Dean Jerry from James Cook University (JCU) said: 'We've essentially got a list of all the genes that the oyster uses to produce a pearl and now we just need to identify which of those genes make the nicest pearls.'

'Basically, we'll be testing each gene in thousands of oysters to identify just five or six genes that make the pearl round, shiny and a pure gold colour.

'Making a pearl is a very complex process and is also very costly. A pearl farmer can produce many pearls before he comes across one that's of substantially high quality. We're hoping to greatly improve the percentage of gem quality, high value pearls that are produced,' Jerry said.