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Engineered cash cows set to unleash fresh storm on food safety


Monday 27th January 2003

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New Zealand scientists say they have produced the world's first genetically-modified, cloned cows whose milk is intended for food, a breakthrough that also points to the next likely controversy to embroil the biotech business.

The scientists at the Government's Agresearch science centre at Ruakura, near Hamilton, said they had produced a herd of nine duplicate, transgenic calves whose milk boosted yields of two types of caseins by up to 100 percent.

The two key proteins are a boon to dairy manufacturers because they help liquid cheese to solidify and they also drive off whey, a watery by-product that is unwanted in the curdling phase of cheese-making.

Agresearch won permission from the Environmental Risk Management Authority (Erma) in 1999 for two parts of its original project to create up to 90 engineered holstein-friesian cows, then claimed to be worth between $2.5 million and $3 million.

The most controversial part of the research -- putting a copy of a human myelin basic protein gene into cattle cells so the beasts would secrete the gene in their milk -- was held up in regulatory delays and court battles, but eventually approved.

Then in 1999, the scientists were given the go-ahead for two piece of research related to dairy production.

One was to knock out of transgenic cattle the gene that controls beta lactoglobulin, the main whey protein in the milk of cows. This protein, thought to bind fatty acids for the benefit of animal young, is not found in human milk, and causes allergenic reactions in some infants and adults.

The other was to insert additional copies of two cattle milk casein genes to produce milk with more protein, without reducing the amount of milkfat already produced.

For every percentage point the casein content of milk could be lifted, the dairy industry would benefit by $100 million. But conventional selective breeding to lift the protein level would be accompanied by a drop in the fat production, which is important for butter and cheese manufacture.

Today, the researchers, led by Goetz Laible, told Agence France-Presse (AFP) news agency the technique delivering extra casein, if taken out of the lab and adopted by the dairy industry, offered "substantial economic gains".

It could be widened, to "tailor" milk for human consumption, they said.

Until now, scientists have genetically modified and cloned farm animals for medical research.

For example, inserting specific genes in a sheep can produce a valuable protein in its milk which can be harvested for new drugs, or producing pigs with specifically deleted genes can gain tissues for human organ transplants that face less risk of rejection by the patient's immune system.

Also, some pedigree animals have been genetically duplicated for commercial reasons, such as selling clones of livestock that are champion producers of milk.

But this is the first case in which a cow has been both genetically engineered and cloned to produce an altered milk for human consumption, rather than for medical research.

New Zealand has a moratorium on commercial release of engineered animals and crops until October 2003, but industry observers said the work by Dr Laible's team would still require a lot of development before it was ready for commercial use.

The scientists inserted into a bovine cell two additional genes responsible for two casein proteins, beta and kappa.

The modified cell was then fused with an egg whose core had been removed -- the standard technique in cloning -- and the resulting embryo then implanted into a cow uterus.

Out of 126 transgenic, cloned embryos, just 11 (9 percent) survived to become healthy, viable calves.

That was even lower than the 20 percent success rate among non-transgenic cloning, whose toll reflects the many risks from genetic duplication.

After weaning, the cows were given hormones to induce lactation, and nine of them produced milk with 8 to 20 percent more beta casein and up to a twofold increase in kappa casein compared with normal cows. The two other cows produced one protein but not both.

Whether or not food from cloned animals is safe for humans is being considered by many countries .

Governments are treading gingerly, given the debate triggered by the first generation of food that emerged from biotech labs.

Genetically-modified plants, such as corn and wheat, had foreign genes slotted into them to boost, for instance, their pest resistance.

Farmers in North America have embraced these crops because they offer big cost savings, and scientists generally agree that they see no evidence so far of a threat to health or the environment.

In contrast, some dissenting scientists, opponents to gene manipulation and green groups, especially in Europe, say it is far too soon to determine the long-term impact of the plants.

Sue Meyer, a biologist with the British watchdog group Genewatch, said cloning and genetic manipulation of farm animals was unacceptable on welfare grounds, as many studies have shown these creatures are prone to sickness and early death.

But there is also concern as to whether food from these animals is safe because of the knock-on effects of genetic tinkering, she told AFP.

"There's going to be enormously important questions about safety and nutritional quality," she said.

"When you do genetic modification, when you introduce genes that change finely-balanced biochemical pathways, the experience we've got from plants is that you can have unexpected effects, raising or lowering other important components.

"If you are directing production in the cell down one pathway, increasing the activity of certain enzymes, you can have effects on other pathways."

If a company sought to introduce cloned, modified food in Britain, public opposition "would just explode", she predicted.

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