Bananas, pigs and the precautionary principle

There’s a nasty fungus which attacks bananas.  Since the 1990s, a fungus called “Fusarium wilt tropical race 4” (TR4) has devastated banana plants across much of Asia and Africa inflicting millions of dollars in losses and threatening the welfare of nations where the fruit serves as a key source of nutrition or export income.  Until recently, TR4 had never been detected in the American continent, but that has now changed. The deadly fungus has been detected in a 175-hectare area on the Northernmost peninsula in Colombia.  So far, 95% of the affected area has been cleared in the hope of containing the problem.  As various experts have said, however, once the fungus has been detected, then it will already have spread.  And to date, no fungicides or biocontrol measures have been shown to be effective against TR4. 

This is not the first time there has been a problem with bananas. Back in the early 50’s, the dominant strain of banana, the “Gros Michel”, was almost wiped out by a slightly different variety of the same fungus.  It destroyed plantations across Latin America, and ultimately resulted in its replacement with a variety called the “Cavendish”.  But all the bananas we eat are clones and so are not subject to the emergence of any significant genetic variation which might limit the effectiveness of the fungus.  They’re sitting ducks.  Lot’s of people in Latin America will again lose their livelihoods in consequence.

The only solution to this problem, if we wish to continue to eat bananas is to breed a new strain which resists the fungus.  There are hundreds of other varieties, but they may not look like the traditional banana and they might taste somewhat different.  Would customers be willing to buy them? Those other varieties could be cross-bred to produce something very similar to the Cavendish, but it would take time.  So then there’s the risk involved in terms of consumer acceptance in starting again with a different variety, or there’s the delay involved in trying to breed resistance into the Cavendish. Of course, genetic modification could help to speed the process up. The genes which gave resistance to the fungus in other varieties could be identified in the laboratory and inserted into the existing bananas on the market with probably a minimal difference in the taste or colour.  But we know that GM foods are not acceptable in Europe, and Europe is a significant market for fruit growers. 

Quite why it is unacceptable is a puzzle.  The fruit and vegetables which we now eat look and taste very different to those our ancestors ate. Over the centuries, by hybridisation of the various varieties, plant breeders have succeeded in making fruit and vegetables which are far more resistant to disease, grow much better and, sometimes, even have a better taste.  All this is by means of genetic manipulation. But the public imagines this to have been ‘natural’ genetic manipulation. It is perceived to be carried out by ‘gardeners’ wearing gardening gloves, rather than scientists in white coats using CRISPR gene editing.  Of course the end result is the same, it’s just that the ‘natural’ variant is not subject to checks to see if it affects our health in the long term, whereas the genetically modified variants are.  Except in Europe, where they are banned because of the precautionary principle.

So what is the precautionary principle?  It’s part of European law and will, apparently, be abandoned when Boris attains his version of Brexit.  Essentially, where the European institutions decide that the risks involved in some proposed technological or scientific advance cannot be predicted with sufficient certainty, and where the downside might possibly be very significant, then it is for the scientists to show that it will not do any significant harm before permission is given for the work to be done.  Of course, although defined in legal terms, the end result is an entirely subjective process. By definition, It’s guesswork what any unknown unknowns will be.  And so we are saying that we should stay with what we know, if we think that the alternative might, according to some lobby group, just possibly be some sort of Armageddon. 

But what would it have been applied to in the past had we known then what we know now?  I suppose that as coal mining could be argued to be the ultimate cause of global warming it should have been subject to the precautionary principle and banned. And so the Industrial Revolution would not have happened. Similarly, oil exploration should not have taken place, meaning that we would have no plastics and would have opted for steam as the motive power for cars – apart from the lack of coal to produce it. The Romans should have hesitated before introducing concrete as a building material for the same reason – its highly significant carbon footprint. Indeed, it was used to construct the emplacements on the coast of Normandy which housed the guns which killed so many thousands of Allied troops during the D Day landings.  And then there's steel which was used to make swords and now guns, tanks, aircraft carriers and fighter planes.   Why not ban fire itself considering the damage it can do to us - even though fire enabled us to start cooking food and so extract more digestible goodness from it, something which has
immeasurably enhanced our lives.  But this is the point – every single new development can and usually does have unforeseen consequences – both good and bad.

As far as I know, however, this principle has only been applied to genetic modification. I can understand the hesitation involved in the genetic modification of humans – eugenics does not have a good reputation. We don't want really to encourage people to take after Hitler.  But preventing genetic modification of plants in order to make them more disease resistant or more prolific in difficult climates?  Why not?  Well, it is because there was fear of what unintended consequences there may be, a fear underlined by the environmental lobby which does not like big corporations interfering in nature for profit.  But, in other parts of the world, GM crops have existed and been eaten for decades and so, fortunately, our neighbours have been the guinea pigs, with no apparent deleterious side-effects.  In Europe, therefore, we should now instead have strict regulation of our steps into the unknown, but not ban them outright. Technological and scientific development is usually beneficial for us.

So then, we turn to pigs.  They will be the next controversy.  It seems that a group of scientists is very close to producing pigs whose tissue, if implanted into humans, would not trigger an immune response.  It has been found that there are 3 molecules on the surface of a pig’s tissue which tell our immune systems to reject it. These can all be removed by that dreaded genetic manipulation.  Tests are likely to be carried out in the next year to see if it’s worked.  Why is this so important?  Well, because pigs’ organs, if not rejected, can be used as transplant organs.  They’re about the right size and function in the same way.  So then we could have kidney or heart transplants without having to ‘harvest’ them from fellow human beings. The idea is that they would start with kidney transplants as, if they failed, then the patients could simply go back on dialysis.  If they worked, then the next step would be heart transplants.  In the UK, this will probably be accepted as ethically sound. In the rest of Europe, I’m not sure. 

But what about the Vegans?  Jehovah’s Witnesses still refuse medical treatment which involves blood transfusions, because blood is supposed somehow to contain the spiritual essence of a human being.  Will Vegans join them in refusing medical treatment because another species has had to give up its life to ‘donate’ the required organ? I do hope that they will stick to their principles!

Paul Buckingham

21 August 2019

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