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GM food has had a terrible press, but without it we would all starve,
argues biologist Olivia Judson, March 2007.

I like genetically modified (GM) food. I'd happily tuck into a bowl of
GM soy; I'd even choose it over a bowl of organic soy. I know this
sounds eccentric: genetic modification is usually decried. But while
much has been made of possible risks, little is made of the considerable
and real benefits. Genetic modification is a useful tool that could have
helpful impacts, particularly on the environment. Indeed, in my view,
support for GM is a green position.

Genetic modification sounds complicated. But actually, it's simple.
There are only two things you need to know to make sense of it. The
first is that a gene is a piece of DNA that contains the instructions
for making a protein. Different proteins do different jobs within the
body. Lactase, for example, is a protein that allows you to digest milk.
The second thing you need to know is that genetic modification just
means copying a gene from one organism - say, a jellyfish and inserting
it into another - perhaps a rabbit - so that the receiving organism can
make a new protein.

Today, genetic modification is a routine technique in laboratories
around the world. Since the potential for it was discovered, 30 years
ago, millions of experiments with it have been done. One of the most
common modifications is to insert a jellyfish gene into something else.
Why? The jellyfish Aequorea victoria has a gene for a protein called
green fluorescent protein. The protein glows green when you shine blue
light at it. If you add the gene for green fluorescent protein to the
end of some other gene, you can see when that other gene is being used:
a little green light goes on. This doesn't harm the organism - and gives
us a way to watch what's happening in the cell.

What's more, there's nothing preordained, or even fixed, about which
organisms make which proteins. As organisms evolve, some genes fall out
of use and disappear, and new ones are added. From time to time, the new
ones arrive from other organisms: in other words, genes sometimes jump
from one species to another. For example, the fungi that live in cows'
stomachs appear to have taken their genes for digesting cellulose from
bacterial co-occupants of the stomach. (Cellulose is the stuff that
plants put into their cell walls; we find it rather indigestible). There
are several ways this can happen. And when we genetically modify an
organism, we mimic this jumping.

The great advantage of GM is that it allows us to make precise tweaks to
a plant or an animal. For thousands of years we've been doing genetic
modification in a far cruder way, by selective breeding. Through this,
we have created extraordinary varieties of animals and plants, taking
them far beyond their natural state. From wispy grasses, we have
developed new varieties of wheat and corn impressive giants with plump
kernels that we can harvest with machines. And we've bred exotica such
as featherless chickens and super-muscly cows.

Nonetheless, selective breeding is limited. Suppose you'd like to breed
lines of corn that use less water. If none of your corn plants are
efficient at using water, no amount of breeding will make a difference:
you have to wait for the right mutations to appear. (Mutations are
random changes to DNA; they occur naturally, when the DNA-copying
machinery makes a mistake. However, they can also be induced.)

In the 20th century, plant scientists in the US and elsewhere began
bombarding seeds with chemicals and high-energy radiation in order to
cause mutations. The seeds are then grown into plants to see whether
they have any useful new traits. This mutational bonanza has given us
some enormous improvements in plant agriculture. But it's a crude,
haphazard approach and may never succeed in generating the trait you
want. Ironically, in contrast to GM, which is one of the most highly
regulated processes in agriculture, this random approach is unregulated;
unwanted mutants are just thrown out with the rubbish.

Why bother with any of this? Like it or not, the history of agriculture
is a history of beating nature: all agriculture is unnatural it has to
be. Much of what occurs in nature is inedible, or meagre in quantity.
The ancestor of the potato, for example, is poisonous. Moreover, growing
crops in abundance is difficult. Lots of other organisms like to eat
what we like. To have a harvest, a farmer has to defeat slugs, pigeons,
rabbits, deer, rats, squirrels, moulds, aphids and weevils - not to
mention weeds. It's remarkable that any of us has anything to eat, let
alone that, in the West at least, we've made food plentiful and cheap.

We've done this by employing a variety of tools. Genetic modification is
just another one. Like any tool, we can wield it well or badly. It's not
a silver bullet: it won't solve all our problems. But all farming, be it
organic or 'industrial', is bad for the environment. All farming puts
land under cultivation, erodes the soil and requires pest control.

Organic farming, indeed, takes more space than regular farming. (And
here's an irony: to control pests, organic farmers often use Bacillus
thuringiensis, a bacterium that makes a protein poisonous to insects.
Inserting the gene for this protein into a plant is one of the most
common genetic modifications.) GM could help us to grow crops with a
higher yield on less land, using less water, and spraying fewer
pesticides. Bring it on.

[www.telegraph.co.uk]