Words and Pictures

with Elizabeth Walton

DNA stirs up a stew

What’s cooking in our biotechnology labs? A dietary revolution, full of genetic modifications even sci-fi writers couldn’t dream up, writes Elizabeth Walton, in The Weekend Australian…

I used to be a real sucker for those little white crystals of sugar sprinkled into coffee – way back when there was a significant difference between a jelly baby and a jellyfish.

Remember? One was a colourful sweet, the other a Japanese seafood delicacy. The distinctions became a little blurred when the CSIRO’s tropical agriculture division began inserting fluorescent jellyfish DNA chains into sugarcane to trace molecular activity in the sugar. So I figured, why not go the whole DNA modified hog and stir the blubbering sea creature right in? I must admit though, the tentacles poking out of the cup are rather unpalatable. I could always chop them off, but surgical technology is just so primitive.

There must be some other way, such as isolating the tentacle genome, turning it around and re-inserting it backwards. It worked for improving tomatoes – why not for inhibiting tentacle growth?

In the eyes of Dr Gregory Harper, a research biochemist with CSIRO’s tropical agriculture division, fiddling with the genes of a jellyfish as a way of getting rid of tentacles would be akin to using a sledgehammer to crack a walnut. It’s overkill. You might get the desired effect, but there is little point in using an extreme technology to do something that can easily be done with tools that are readily available and very cheap to use.

Harper is researching ways to create 100% tender beef. But he doesn’t expect science to discover a DNA chain responsible for producing the perfect cow. Using technology to improve vegetables is one thing, he says, but genetically improving meat is something different altogether. “In plant technology, like the FLAV SAV tomato, [one with the back-to-front gene], you can knock out the one single characteristic. Tinkering around with animal muscle, on the other hand, is much more complex, and fraught with difficulty.”

Attempts to use growth hormones in the 80′s to create a super pig failed because pig bones couldn’t support the growth rate. Changing a cow’s collagen enzyme could potentially reduce the strings of gristle that downgrade beef quality, but as with the super pigs, the contra-indications make it a pointless exercise. “You’d be heading off into no-man’s land,” says Harper, because “the collagen contributes to the health of the living animal.”

“The idea is to use molecular biotechnology as a diagnostic tool, rather than to modify the animal – particularly if the consequences are not known.”

Scientists, he says, can use genetic diagnostics to analyse the effects of farming practices on beef quality. Farmers can then make informed choices about what and when to feed, and the best time for culling.

Ten years ago, food faddists were fond of quoting the old maxim, ‘you are what you eat’: if you too much doughy white bread, you go all pale and puffy; too many carrots will turn you orange, and so on. So what do you become when what you eat is genetically improved?

When I was a child, a Mac was something you ate at a hamburger store. These days, the term refers to the act of eating an overcoat. That’s M-A-C, as in Modified Atmospheric Coating. Raw vegetables are covered with MAC before they hit the supermarket, to extend their shelf life. It’s the latest GRAS (Generally Recognised as Safe) technology. Chomp. If you are what you eat, then I guess eating MAC protected vegies prevents you from deteriorating on the shelf.

If you look closely at a piece of cheese, can you tell if it contains genetically engineered rennet? No, nor can I. There’s no use asking the supermarket for a piece of cheese with non-genetically engineered rennet, please, because the supermarket can’t tell either. That’s why the Australia New Zealand Food Authority is calling on the Federal Government to introduce mandatory labeling for genetically engineered foods, to inform consumers about the products they are buying.

Cheese rennet is one of the few genetically engineered products on the market in Australia. Farmers in the US have planted more than 1.2 million hectares if genetically engineered crops this year, including eggplants, tomatoes, corn and rice – just about everything you can think of.

Following a recent outbreak of e coli,   which required the recall of  more than 11 million kilograms of meat, the US government rubber stamped the approval of irradiated meats for mass consumption, with no intention of introducing a labeling system to distinguish products of one technology from any other.

The Australian public has made it clear that irradiation is unwelcome here, possibly because of fears that it may introduce volatile chemicals into foods. But is this a real risk or an emotional response to a new technology? The World Health Organisation’s report on irradiation, which was commissioned by the Australian government, found that irradiation creates the same hazards as applying heat through any other food-processing technique, such as steaming, baking – and dare I mention that other 80′s food processing phobia – microwaving.

“The thing is,” says Australian Food Council scientist and technical director Geoffrey Annison, “people have always messed around with the food supply. The only difference between old technologies abd products like Monsanto’s Roundup Ready soybeans [which are genetically engineered to resist herbicides], is the rigorous, scientific analyses they have been subjected to.

“It”s not like the introduction of triticale – a cross between wheat  and rye which was introduced last century – which had no regulatory hurdles to test if it was safe.”

The classic example, Annison says, is the cross of the soybean and Brazil nut. Scientists tested the hybrid before its commercial release and discovered that the nut’s allergen was transferred to the bean. The new product posed a potential threat to any people who would normally steer clear of Brazil nuts because of a  known allergy – yet think they can safely tolerate soybean based products.

Consequently, the new plant, which was originally designed to increase the soybean’s protein content, will never be released for human consumption. Without this thorough testing the product could have been released before the dangers were revealed.

“We’re very lucky that we don’t have to experiment with foods in a haphazard way, because of our strict controls,” Annison says. “You only have to look at the broad range of foods available in supermarkets to see the benefits. Twenty years ago, chicken was a very expensive luxury food. Improvements in food technology have changed that around, and chicken is now one of the cheapest foods available.”

So why the resistance? Janet Norton, co-author of the book Altered Genes, has undertaken a national study of consumer attitudes toward genetically engineered foods for her PhD thesis at Central Queensland University. Her research indicates that the Australian public is willing to accept plant-to-plant genetic transfers, since it is a logical evolutionary progression for vegetables to crossbreed.

“But what’s the chance of nature throwing a fish gene into a tomato?” asks Norton. “The problem is, we just don’t know enough yet. Consumers are concerned about what the effect will be on future generations.”

They’re also reluctant to trust scientists, she says, who have a knack of getting it wrong – as was the case when mad cow disease crossed the species gap after scientists said it could never happen.

“Just don’t think about DDT or nuclear power – the scientists tell us they’ve tested, they tell us it’s safe, but repeatedly, it’s not. And we don’t find out until 20 years down the track. Once you take that step, there’s no going backwards.”

She’s right there. No doubt about it – you can take the jellyfish out of the bowl, but you’ll never take the jellyfish out of the sugar.

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