Breeding GMO contamination free corn... possible?

Just adding this to the thread which may be of use to others looking to keep their landrace as clean as possible from cross-pollination with commercial, large-scale corn production.  Credits to Cy Cobb who found out about this gene.....

Just looked this Ga1s gene up and it looks interesting.  The somewhat complicated, but thorough, story behind this can be found in there article here:  https://www.nature.com/articles/s41598-022-25261-8

The abstract from that is pasted below.  I'm thinking it may be difficult to guarantee that no cross pollination with other commercial corn had occurred.  Still, this may offer some initial protection and then other means used to keep the landrace 'clean'.  Looks interesting!

So, I was just perusing the Experimental Farm Network seed offerings, and one of the corn varietals offered speaks of a Ga1s gene that resists contamination by GMO corn.  Does anyone have any more information about this?  I'm not sure if the GMO pollen won't fertilize the seed (land on the silk, but not make a kernel), or if it will make a kernel but the seed won't survive germination?  It mentioned this is a very old gene that goes back to wild corn & is found in popcorn (first domesticated).  This makes me think that the GMO pollen won't even fertilize the seed, but I don't know.

I have questions...

Is this gene likely to be found in other historical "Indian" corns?  

At what point in domestication did this gene disappear?  

Since it's found in teosinte & popcorn, would surviving flint types (similar to popcorn) contain this gene?

If confirmed seed containing Ga1s was grown in a field, detasseled, then pollinated by someone else's landrace/grex, wouldn't that seed produced on those ears now be GMO marker free?

Where would an average person get seed tested?

My thinking is that for someone that lives in commercial field corn country, and has to take special precautions to maintain GMO free corn, could this be an avenue to "screen" or "filter" out any GMO contamination in their population?  Since the resulting seed could only be pollinated by Non-GMO pollen?  

Personally, if I grow it, I eat it.  However, if I could keep my corn from receiving pollen from miles of commercial corn in all directions, I'd prefer that.  Just wanted to explore some "new to me" information, and didn't know if others have anything to add?

Joseph Lofthouse wrote:John Weiland,
I have merged your topic into this topic. I hope that helps.

All good.....a better place for this discussion.  Thanks!

Edited to add--  A crucial line for me in reading the abstract is this >>>"Some Ga1-s dent hybrids excluded as well or better than some popcorn lines suggesting that identification of hybrids comparable to popcorn is possible."  What this means is that popcorn, as a corn 'type', is not 100% resistant to cross pollination by pollen from a ga plant.  Additional work will need to be done to determine if those other less-resistant popcorn lines are that way due to loss/absence of the allele in those lines or if some other factor suppresses their 'resistance effect' allowing for the ga pollen to successfully fertilize.  Nevertheless, having Ga1-s beats not having anything and reduces the probability, if one already has barriers in place to reduce pollen drift, of getting a cross-pollination event.

Has anyone done any big-picture assessment of how much uncontaminated corn remains in North America? I was under the impression that it was a Pandora's box situation and that you had to be quite a distance away from any commercial fields to still be in a "safe zone." So it seems that the entire midwest is suspect. And I'm also curious how many seed companies are selling varieties to the general public that haven't been vetted...your neighbour could plant a bed of sweet corn and unwittingly introduce pollen to your landrace without your knowledge.

We're still GE-free by statute in this country, but all bets are off since a shipment of corn arrived about 20 years ago without going through the proper channels. There's also been field trials at a couple of our universities with brassicas and onions and their protocols were sloppy, so we really don't know how far things may have spread in those species. I'm hoping that at least with the remaining crops we can keep a bit of a refuge going here and provide uncontaminated seed to people overseas who want to breed with it, but it's a political football being kicked around by well-funded lobbyists at the moment.

Phil Stevens wrote:Has anyone done any big-picture assessment of how much uncontaminated corn remains in North America?

Baker Creek, the largest heirloom seed company in the usa submits every lot of corn seed to genetic testing. Their methods can detect 1 contaminated kernel in 10,000.

Biologically, pollination is highly localized. Corn is more likely  to be self-pollinated (~65%) than to be pollinated by even it's closest neighbor (~32%). Ninety nine  percent of pollination occurs from selfing, or from plants within 5 feet.

In a 10 mph wind, pollen has already fallen below silk level within 25 feet. By 100 feet, chances of cross pollinating from a nearby patch fall to much less than 30 PPM. Those quadratic dilution factors accumulate really fast!!!

Phil Stevens wrote:....I was under the impression that it was a Pandora's box situation and that you had to be quite a distance away from any commercial fields to still be in a "safe zone." So it seems that the entire midwest is suspect.....

I also like use of the Pandora's Box metaphor for the situation, but for an additional reason and that is the issue of what constitutes 'contamination'.  To take one of the easier examples, early generation GMO for an arbitrary 'trait X' would have had the trait that benefited the farming operation on some level linked, physically, to a separate trait for antibiotic resistance as a consequence of the assembly process to produce that GMO line.  It made it rather easy then for a testing service to detect the DNA for the 'new trait' as well as that for the antibiotic resistance still linked to the new trait.  But if the chromosome harboring that module gets crossed into, say, a garden crop of the same species or a closely related weed species, it *can* and likely *will* begin undergoing mutation if there is no selective advantage now being conferred by that module in its new genome.  If, for example, the 'trait' in question was stunting the height of commercial corn in order to be more easily harvested by a large combine and *if* the home gardener happened to want taller corn to keep the cobs higher on the stalk, then that stunting trait, over time, would start to drop out of your seed collection year after year as you avoided keeping seed from the stunted stalks.  And since no known selection is occurring at the antibiotic resistance gene, it too will accumulate mutations over time just by chance.  Let's not forget as well that mutations are not always just small changes, but can be deletions....wholesale removal of chunks of DNA by the plant's genome maintenance mechanisms.

And this is where the issue gets quite murky:  Because how much DNA remaining from the module is enough to call it 'contamination'?  In the case above, a few mutations in the right locations on the module would be sufficient to render the stunting gene 'inoperative' and the plants harboring the inactive copy would be tall.  Seed saved from that plant would have an inactive stunting gene, but its DNA would still be there, albeit in mutated form. It's likely that most genetic testing services are just looking for small snippets of the module DNA when they test and give that a score of 'positive'.....and fair enough if that's enough for the customer to wish to jettison their seed stock.  (The newer gene sequencing technologies that have emerged from the human genome sequencing projects globally are massively reducing the cost of whole genome sequencing of organisms:  Easily the genetic testing services in question soon will be sequencing the entire genome of a received sample and looking for the presence of cross-pollinated genes in question using these methods.) But at the other extreme are 'gene edited' crops---considered non-GMO in the US if I'm not mistaken, but still under regulation in the EU.  In these cases, it would be nearly impossible to determine if the change in the DNA was a result of natural variation or something put there deliberately through laboratory procedure.

No clear answers here, but it will be an issue to deal with as gene flow from modified crops to unmodified crops and to wild species continues to occur and as those gene modules 'degrade'....genetically speaking.....over time in their new background genomes.

Ok, unpopular topic here, but in the interest of being objectively curious, how physically bad is GMO contamination for a person or their landrace corn population?  I am not an expert on such things, and have my own philosophy.  However, I am interested in knowing what you all think since we've cracked open the discussion?

I'm 100% cool with selective breeding for certain traits within a natural population.  That's what humans have been doing since we first started farming with saved seed.

However, I understand that modifying/splicing genes from other species is something different altogether, and serves the purpose of making the plants (in this case corn) resistant to pesticides and other commercial sprays for the sake of maximum profit and "feeding the world" through international export, etc.  I also know that several countries have banned the import of U.S. GMO corn for their populace.  I am not about to cover every country or their motives for doing so, but excluding partnered trade agreements, that essentially leaves the question of "Will this franken-food be harmful to our people?"  Are they simply uneasy about the idea, or is there more to it?  

Now, for the personal-use scale producer of flint/flour/dent corn in the Midwest, where does that leave you?  I do have methods/means for isolating/protecting, but does this potentially have a place in landrace development?

The same reasons some people incorporate disease or fungus resistant F1 hybrid varieties of crops into their landrace population could be said for this as well.  If someone had some pollen drift over from a commercial dent corn field & land on a few of your landrace corn silks resulting in improved yield or increased fungal resistance in future generations, would that not be a benefit?  Now, fast forward to 15 years later, and now your population has been selected each year for productivity, faster dry down time, fungus resistance, etc.  I'm not talking about moving your entire population over to a commercial corn, I'm talking about a measured influence over the years.  Sure, it's not pure heirloom corn anymore, but isn't that the point?  It's got the potential to be better corn for the individual grower.  Of course, I'm not getting into patent infringement of XYZ Corporation because it's not going to be sold as such, but for personal use/animal feed, does it matter?

I'm purely just trying to "flesh out" an idea, and am interested in what you all think?  Feel free to disagree with me, as I'm simply exploring a theory and am very open to criticism.  The Pandora's box question of how much untainted corn seed is really out there just had me wondering...

I think technology is rad. That includes biotechnology. I am generally not afraid of transgenic insertions, though some baseline level of quarantine-caution is called for when building new things that could escape. My opposition to GMO, to the extent that I really have one, is that when it's used for evil, that sucks. I oppose greater and greater uses of herbicide (or if I'm being honest, any use of herbicide) and so GMO designed to sell more Roundup is icky-bad. I also oppose the patenting of organisms, which isn't exactly a GMO thing, but they happen to go hand-in-hand because of the way we've structured things legally.  

I live in a state where lots of corn is grown, but I live in the woods north and east of where that really takes place and through a combination of distance and the air being combed by the forest, I think the chance of any but the tiniest contamination taking place is really unlikely. And as it does happen, I'll just keep selecting for the traits I like and inserting genetics from foreign sources I trust.

The main problem I have with the industry-led push for GMO crops is that it's about, well, industry. There is nothing about the technology that says "let's work with nature, who has a 3.5-billion-year head start on us in terms of selecting chance mutations for adaptation to environmental conditions." It's more "this problem looks a little bit like a nail I once saw. We have a hammer, so let's use that!"

It's also not terribly respectful of the communities and cultures who have cultivated crop plants for hundreds or thousands of years to say "we're going to take your ancestors' hard work and your unique heritage, place it under IP restrictions, and splice little bits of it into other things without consulting you or paying you royalties."

Then there's the big one. The precautionary principle. We simply do not know how GMO implementations will turn out in the long run. We've seen some spectacular downside already with things like terminator genes, 'cide resistance in weeds, and unintended wipeouts of monarch butterflies by Bt-laden pollen. We have no idea what some of the developments in the pipeline now will look like after a few dozen generations in the field, but one of the features of unintended consequences is that they tend to be negative and affect those who weren't in on the profit margin when the seeds were sold.