Science Questions

Why should GM seeds be sterile?

Sat, 15th May 2010

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Roland Williamson asked:

I am one of those totally torn by the issue of GM crops. I understand the argument (I think) but the leap forward from annual selection and breeding of crops is over shadowed by the unnecessary control by the developers whereby they retain control of the seeds. How can that benefit man?


We put this question to Dr Jim Haseloff, from Cambridge University:

Jim -  I think it’s an extremely interesting question and with synthetic biology, a lot of us are struggling with this idea that are shifting towards modified biological systems that are based on parts, and that those parts might be open-source and the technology is very cheap, so there’s certainly a potential for allowing access in developing countries to technology which can dial straight into important sustainable technologies.  The current model for biotechnology involves protecting elements and preventing other people from using them except under license.  So, this idea of protecting or removing fertility in seeds can have a bio-safety aspect, but it also can have an aspect of limiting use.  So, I think this is a question not for scientists but for society.


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Roland Williamson asked the Naked Scientists: Re: Banana Medicine by Harriet Dickinson   Love the site - better get that in!   I am one of those totally torn by the issue of GM crops. I understand the argument (I think) but the leap forward from annual selection and breeding of crops is over shadowed by the unnecessary control by the developers whereby they retain control of the seeds. How can that benefit man? Politics has starved far more than ineptitude.   Regards, Roland Williamson. What do you think? Roland Williamson, Sat, 11th Jul 2009

The sterility is not just for economic reasons, (so the farmer has to buy new seed every year).

Theoretically sterility should prevent GM crops being mixed or crossbred with “natural” crops.

If you were a “GM-free” farmer you would not want your neighbours genetically modified crop being mixed with or crossbred with your “natural” crop.  RD, Sat, 11th Jul 2009

The most important reason is, as RD says, to prevent crossbreeding.  However, the problem is potentially far more serious than just contaminating non-GM crops; there is a risk of the GM crops not only interbreeding with non-GM crops and out-evolving them, and in effect, killing them off, but also interbreeding with dissimilar plants and killing them off too.  When I say 'killing them off' here I'm referring to the GM organism mutated crops supplanting the non-GM varieties in the same way that evolution works; the mutated plants might survive better than the original plants, leading to their decline and extinction.

The problem I have with GM crops, and GM meat too, for that matter, is that I think the testing period has been far too short.  I can't see an intrinsic problem with GM; it seems like a very good idea to me.  It's just that considering the importance of what we're dealing with here, and how it's such a fundamental part of our diets, I think a couple of decades is too short a testing period; I think they should have been tested for a couple of centuries before being declared safe.  We just don't know what the long term effects will be, not just on individuals but across generations. LeeE, Sat, 11th Jul 2009

Why don't farmers/selective breeders have to jump through the same hoops? Their organisms are just as GM as scientifically GM organisms. _Stefan_, Sat, 11th Jul 2009

Can we afford to wait a couple of centuries?

And as _Stefan_ says, we've already been genetically modifying our food for centuries. 2000 years ago a banana tree as we know it didn't exist, but after selective breeding we today have a pretty efficient fruit producing tree. If we can artificially GM our crops to produce more food faster then why not, with the worlds population as it is today we're going to need all the food we can get. Madidus_Scientia, Sun, 12th Jul 2009

Selective breeding is not really the same as genetically modifying something.  With selective breeding you can only combine traits between organisms that can already interbreed whereas GM is most often used to combine traits from dissimilar organisms, ones that cannot naturally interbreed.  GM is not just about making selective breeding more efficient.

There are risks associated with selective breeding, of course; inbreeding being a classic example.  The scope of the risk though, is confined to organisms that can already interbreed, and if they can already interbreed it's likely that that specific combination has already occurred and failed, or succeeded.  With GM the potential scope for risk is unknown.

Can we afford to wait a couple of centuries?  Why has that factor become an issue now and did not arise before GM was possible?  Is it really just coincidence that GM became necessary only when it became possible?

The question is can we afford such a risk?  What is certain is that nothing works 100%.  There will certainly be GM programs that fail, and most of these will be found and discarded before going into 'production', but similarly, the detection process won't be 100% successful either and at some point it is almost inevitable that something dangerous will not be detected before the problems become apparent.  This has happened many times already in the field of pharmaceuticals, so why do people expect it to be different with GM?  Relatively few people need to take pharmaceuticals, especially on a long-term basis, but with food you're going to be hitting a lot more people with something they'll be using constantly. LeeE, Sun, 12th Jul 2009

I don't think it means much whether 2 organisms can interbreed or not. When a new mutation occurs in one line, or an allele in one line has never been experienced by the other line, this is no different from introducing a trait from an entirely different species. And in both cases, the possible effects are not known.

Also, when selective breeders produce new strains traditionally, they have no idea how safe it is for the environment or to eat, because they are new.

The GM issue needs to be examined in perspective. _Stefan_, Sun, 12th Jul 2009

I must agree with LeeE, GM and selective breeding are different. You cannot take a trait present in wheat and get it into a tomato by selective breeding, but you can by GM.

It is not simply the long term effect on the plant concerned, but also the long term effect on other plants/insects/wild animals which may be indirectly linked to that plant. Even in the short term we have seen problems with GM maize pollen killing Monarch butterfly larvae. Any break in the natural food chain can have dire consequences.

To my way of thinking, selective breeding is OK up to a point since it is something which nature will allow, but GM is contrary to natural crossbreeding and has the potential to result in something which could be dangerous to those which rely on it and have a knock-on effect both up and down the food chain. Don_1, Mon, 13th Jul 2009

Given enough time, you could selectively breed to produce almost any trait. We know this because it's already happened through evolution as well as artificial selection. There are also countless examples of convergence.

The GM butterfly-killing-crop was engineered to produce a pesticide as far as I recall. Any plant that produces a pesticide could have had this effect, GM or not.

As Lee said earlier, there's nothing intrinsically bad about GM.

Please, put GM in some perspective.

By the way, I am not advocating against research into the safety of GM. _Stefan_, Mon, 13th Jul 2009

As I said in my first post, I do think that GM is a good idea; the problem is that there has been insufficient time to adequately test it.  The motives for it's early roll-out and aggressive promotion have nothing to do with saving the Earth, it being claimed by some that it is now our only viable option; it's being pushed out so aggressively, even to the extent that attempts have been made to restrict non-GM alternatives, purely to turn a profit. LeeE, Mon, 13th Jul 2009

The incident with the monarch butterfly, I think, is evidence enough that much, much more evaluation of GM crops and their effect on other plants/insects is imperative before any GM plant is released into the open environment.

The big problem at the moment, is that most research is being done by, or funded by the companies keen to promote their GM products. It is, therefore, not so much biased as blatantly predestined to come out in favour of GM. Don_1, Mon, 13th Jul 2009

Heh - a bit of an after thought, but I just thought I'd better mention that it is not the seeds that are sterile but the plants that grow from them. LeeE, Mon, 13th Jul 2009

In Australia there is documented evidence that GM crops cross pollinate
so we may lose the original strain forever.

echochartruse, Sun, 23rd May 2010

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