By KEVIN TAYLOR
Quiet paddocks at Ruakura near Hamilton will soon host a flock of genetically modified sheep with "double muscles," bred to aid research into muscular disease and heart attacks.
The Environment Risk Management Authority (Erma) has approved AgResearch's application to breed up to 100 sheep in the world-first research, which could benefit patients of muscle-wasting diseases such as muscular dystrophy and Aids.
The sheep will be missing the gene myostatin, which regulates muscle growth in most mammals.
Scientists at AgResearch hope to transplant myostatin-free embryos into ewes within six months.
Project scientist Dr Ravi Kambadur said the five-year research would result in sheep with between 20 and 40 per cent more muscle mass than normal.
Dr Kambadur helped discover myostatin in 1997.
It will be knocked out of sheep-skin cells through gene manipulation, in a process similar to the natural mutation seen in Belgian blue cattle, which causes the breed to have larger muscles.
The nucleus of the skin cells will then be transplanted into sheep eggs. Embryos will be allowed to form and will then be implanted into ewes.
This will produce five to 10 genetically modified sheep, which will be used to breed up to 100 transgenic sheep.
Dr Kambadur said myostatin might have a role in muscular dystrophy, and if scientists could find a way to control the gene it could be used to make muscles grow.
Myostatin had been found in high levels in surviving cells of sheep hearts after they had suffered heart attacks.
That suggested the gene might offer some protection against heart attacks.
Dr Kambadur said scientists needed a sheep with no myostatin so that they could do their research.
People would probably notice that the research sheep were more muscle-bound but they would be kept in secure paddocks at Ruakura.
AgResearch has already produced myostatin-inactive mice, with increased muscle mass.
Scientists hope to produce the first mysostatin-inactive sheep within two years.
Dr Kambadur, who is one of a three-member team working on the project, said the research was extremely low-risk for the animals.
The AgResearch application was received by Erma in June last year, before the Government's moratorium on GM field trials came into effect.
AgResearch has told Erma that meat from the engineered sheep will not be put into the food chain.
But if deliberately mutating the gene was shown to produce farm animals with proportionally more meat and less fat and bone, farmers were likely to call for agricultural work aimed at improved meat yield and quality.
In its application to Erma, Ruakura staff said they were looking at boosting the secure area for holding research livestock from 4ha to more than 50ha.
AgResearch already houses cattle for GE experiments on the same site, including one set designed to produce human proteins in their milk for medical research.
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By KEVIN TAYLOR