Wednesday, 13 August 2008

Prince Charles and GM crops, oh dear

Genetically modified crops, that's the subject of today's waffle because Prince Charles has described them as giving rise to the greatest threat to the world since whatever he last got into a twisted-knicker situation about. Oh yes, I remember now, it was man-made global warming. I must not give the impression that I think Prince Charles is a nutter because I do not, I believe him to be a great asset to this country, I also believe him to be wrong on this issue so I had better explain.

Plants are jolly interesting things. I have taken pleasure over many years from sowing seeds in the greenhouse in early Spring and seeing them turn into little shoots, then pricking them out and seeing further development until they are big and strong enough to be planted out in the garden where they produce flowers or vegetables. Of course not every seed germinates and not every seedling is strong and healthy, the seeds that don't sprout just rot in the compost and the weak seedlings are discarded, my garden only holds the finest examples of each year's greenhouse activity.

In an indirect way I am interfering with the genes of the plants by getting rid of the weaklings because I allow the very best plants to develop seeds and collect those seeds for the next year's Spring sowing. When the following Spring arrives and I waddle to the greenhouse I use the children of the strongest plants, some of the genetic weakness in last year's seeds was eliminated when seeds failed to germinate or seedlings were puny and discarded. Over a number of years the plants I sow become marginally stronger because of this. It is the way commercial seed merchants and plant growers have worked for generations. No doubt it takes a very long time to make any significant difference to the average strength of the gene pool in any given species but removing the runts of the litter does strengthen the next generation which is one reason why we can grow more reliable flowering plants and vegetables today than fifty years ago.

On another aspect of the same subject, as I sit here in my study I can look out over the garden behind FatBigot Towers and see a massive London Plane tree, one of the most beautiful examples you could ever hope to find. The London Plane is genetically modified, it is a cross between the American Sycamore and the Oriental Plane. Like many cross-bred plants it takes some of its qualities from each parent and the reason it has been planted in huge numbers in London and many other cities around the world (I noticed loads of them on a trip to the wonderful city of Chicago) is that the particular cross makes it an excellent large tree for urban areas, much better, indeed, that either of its parents.

Both in the selecting of seeds from healthy plants and in cross-breeding plants we make modifications to what would otherwise be the "natural" gene pool in future generations. I do not hear Prince Charles complain about these processes, perhaps because it has happened on his estates since long before they were his estates.

Genetic engineering of commercial crops is different in method, but not in substance, from what gardeners have been doing in their greenhouses for donkeys' years. It might take two hundred years to breed-out or weaken significantly a gene which makes a crop susceptible to a given disease or attractive to a particular pest, and there are many examples of such breeding having been done successfully (for example some roses have been developed which are resistant to blackspot, potatoes which are resistant to blight and lupins which are not attractive to aphids). I see no difference in substance between removing genetic susceptibilities over months in a laboratory rather than over decades a greenhouse.

No one should imagine that selection of strong parent plants and cross-breeding is always successful, sometimes removing the apparently weak gene leaves a plant open to other diseases or pests because the original version relied on the removed gene as its defence against these attacks. Similarly some cross-breeding produces a new plant with all the weaknesses of both parents. But that is part of the process, there is no magic involved it is all about trial and error.

So, what are the risks of genetically modified crops being harmful? There is no evidence that they are.

If we mean harmful to the people who eat the stuff the answer is that there is no risk. Eating cereals and vegetables gives us carbohydrates, vitamins and fibre but it does not affect our genes. During the digestive process we break the vegetable matter down, absorb the good stuff and dispose of the rest. If we eat the wrong things they can poison us but no one is suggesting that genetic modifications to try to make carrots unattractive to root fly turns them toxic, and if it did they would never be sold. There is no apparent danger to human or animal consumers.

That just leaves other plants. Is there a danger of genetically modified wheat causing harm to non-genetically modified wheat? I do not know, but it seems rather fanciful to suggest that any harm can come from a variety of wheat resistant to a particular disease crossing with a variety which is susceptible to that disease. One problem I can envisage is that a gene which makes a plant susceptible to a pest or disease might also make it resistant to a different pest or disease but it would be surprising to find any GM crop being planted commercially until such potential side-effects had been examined.

Maybe there can be risks beyond my feeble imagination, but I have never heard anyone suggest that current GM crops have caused any problem to anything. By happy coincidence, while writing this piece I am listening to the radio and have just heard a spokesperson from Friends of the Earth support Prince Charles. And what did she say in support? Did she say GM crops are dangerous to humans or animals? No. Did she say GM crops affect other crops adversely? No. All she said is that there is no evidence that GM crops can solve food shortages in poor countries. Friends of the Earth, like all narrow-issue fanatical groups, are very astute to latch onto even the slightest piece of evidence in support of their position and all they can say is that there is no evidence that GM crops will solve the problem of starvation in overpopulated countries. That tells us everything we need to know about the evidence of GM crops being harmful.

Incidentally, that Friends of the Earth support Prince Charles's statement that GM crops are harmful on the basis that there is no evidence that they will solve world poverty tells us a lot about Friends of the Earth.

On this one Prince Charles is, I am sorry to say, barking up the wrong end of the stick.

1 comment:

David Gerard said...

Charles didn't hammer home that GM is for Monsanto to take ownership of everything. Scientific opinion doesn't affect abuse of the law.