Gene flow ... again

In my previous post I tried to expose what I think is a huge logical inconsistency at the heart of some arguments against genetically engineered plants. I did so, however, using a very abbreviated argument that, I now see, could only be easily followed by those who know the subject. And that was foolish because those who already know the subject are not the people I hoped would read the post.

As Viscount LaCarte graciously pointed out, "I don't know enough about it to know what the real risks are of getting 'Super weeds' but I can guess what the risks might be to poor people in living in a subsistence farming community never being able to "recycle" seeds and having to always buy new ones every year."

I need to do better, so here goes.

The issue is about something called gene flow. That is the transfer of genes from one plant to another. It happens all the time in nature, when pollen (the male part) from one plant ends up fertilizing the ovules (female) of a flower on a different plant. In some crops, gene flow is vital to their survival. Corn (maize) and cabbages, for example, are obligate out-breeders. That means they really have to cross with another individual. If they don't, the seed they produce is liable to be defective in various ways. Other crops, such as most beans and most tomatoes, are in-breeders. They are perfectly OK if pollen from one flower fertilises the ovules of the same flower. They can cope with pollen from a different flower, but they don't need it.

Genes flow among varieties of a crop and also between crops and their wild relatives, where the flow takes place in both directions, from crop to wild relative and vice versa. The extent of flow, as I said, depends on the usual breeding system of the plant. It can be very high among neighbouring plants of a single out-breeding variety, or very low between an in-breeding tomato and its wild relatives. Ironically, it is only thanks to genetic engineering that we have accurate estimates of gene flow, because the tools of molecular biology allow researchers to track the movement of individual pollen grains.

The existence of gene flow means that there is indeed a risk that genes engineered into one variety of a crop could move into other varieties planted nearby and into wild relatives. If the gene makes the plant resistant to weedkillers then one could indeed end up with nastier weeds than before the engineered plants were deployed, and that is certainly a good reason to be cautious.

Now comes the interesting part -- GURTs, or gene use restriction technologies.

Back in the mid 1990s, researchers discovered that they could add genes to plants that would prevent seeds from germinating. For big seed companies this is business as usual. Their entire operation is based on breaking the historic cycle that has underpinned agriculture for almost all of its existence. Farmers save the best of their harvest to sow next season. The growth of specialized seed companies, and especially the development of F1 hybrids, has been devoted to finding ways to encourage farmers to buy fresh seed every season. Seeds that fail to germinate unless treated with some chemical available only from the company are the logical outcome.

GURTs make it possible for a company to invest in genetically engineered varieties with no fear that farmers who like the variety will simply save their own seed and thus save themselves the cost of seed. As a by-product, almost, GURTs also address the issue of unwelcome gene flow, because any seed that arises from the pollen of an engineered plant with built in GURT will fail to germinate.

That, surely, is a good thing. It overcomes the objection that genes engineered into plants will escape and find their way into wild relatives or neighbouring crops, because if they do the seed they are in is effectively dead. Logically, anyone who is worried about gene flow ought to welcome GURTs.

Instead, people have said that Terminator or Suicide Seeds rob poor farmers of the ability to save their own seeds.

Yes, they do. But that is a good thing, because it prevents the poor farmers' crops from accumulating engineered genes. In the event that there is an engineered crop growing nearby it is indeed possible that a very small number (1 in 10,000? 1 in 1,000,000?) of seeds in another farmer's nearby plot of the same crop might receive foreign pollen. But as those seeds also receive a suicide note, they pose no problem to future generations of that farmer's crop.

Poor farmers, small farmers, farmers eking out a living on marginal lands are not in the market for genetically engineered crops. The companies know that. Not one of them is working on genes that will help those farmers. Those farmers are not going to be buying genetically engineered crops and then complaining that they cannot save seed. They are unlikely even to be near farmers who can afford to grow genetically engineered crops. And if they are, crops with GURTs -- will stop the spread of engineered genes.

So why aren't protestors actually welcoming GURTs?

Once again, this is my personal opinion, personally speaking.