Yes, I'm familiar with the concept of retroviruii contributing to our genome. However, retrovirii are only one means of transfecting cells with desirable genes. If they are utilized, their entire genetic component is gutted (apart from the elements that allow it to upload its payload into the target genome: reverse transcriptase etc) and replaced with the gene that we wish to express. Thus, it can incorporate this gene into the plant, but without the requisite genes to copy itself, there will be no other retrovirii produced, rendering the danger to us from accidental transfection null.
Fair enough.
I'm afraid I don't understand your concerns regarding exons, introns and prions. True, prions are implicated in certain diseases, not least CJD. However, they are a protein product. They are detectable. They will, by definition, be produced from the exon sequence of the genome, if produced at all: thus it is possible to monitor for them.
We can only monitor for the existence of prions that we know represent a danger and need to be searched for. We didn't know to search for the prions that cause Mad Cow (CJD) until people became diagnosed with it. Unfortunately, CJD takes 10 to 15 years to manifest itself; the damage had long since been done.
You say that GM foods are not regulated, and this appears to be untrue. From wikipedia:
With regard to FDA regulation, the FDA does not regulate GM crops, although they do regulate GM animals. I am searching the FDA website and finding nothing relating to GM or GE crops. The USDA has some information online, but not relating to testing or regulating GE crops that I can find. The standard for regulation for GM animals is 'substantially similar' as you stated. There is a great deal of controversy over what 'substantially similar' means.
Be this as it may, all of those attributes (though perhaps not improved taste) are vitally important in addressing those countries that suffer from food shortages. And that isn't to say that GM food won't be made healthier for us either.
You're brushing aside all secondary concerns, including pollution of ground water due to over-application of herbicides.
And I'll have to disagree with this. As shown by my Wikipedia quote above (not the most reputable source TBH, but their referencing seems to stand up to casual scrutiny), the bar is quite high for safety testing. I'd happily eat foodstuffs that have passed this testing, and in all honesty, probably do.
Yeah, it's a done deal, pretty much. But no, the testing you think is being done is not, at least to the extent that I can determine. Not in the US.
http://www.ers.usda.gov/data/biotechcrops/
If crops are sterile, then they're obviously not going to be able to adapt to environmental stressors such as disease, correct? It's a moot point.
Not a moot point. The crops are all nearly genetically identical; homogeneous and not heterogeneous as wild or domesticated 'natural' species are. Given an infestation or an infection of some new threat, some heterogeneous plants might have a natural resistance; those would tend to survive and reproduce. Homogeneous plants do not have that diversity and cannot respond in that manner, infection or infestation that kills one will kill all, limited only by geographical and time vectors.
Hopefully if such a situation arises the next generation will be adapted to survive it.
How? By genetically creating a cure between one growing season and the next? And how to grow the seeds necessary to provide the next generation?
And this is not a problem specific to GM foods: any major crop type could hypothetically fall victim to such a predator. True, wild-type corn may have an adaptation that allows resistance to a certain disease: but the vast majority of the crop will die out anyway.
Vast majority? That's speculation. Might be true, depending upon the infestation or infection. Might not. In any case, it beats 100% infestation when all the corn consists of essentially the same plant.
If we're talking about a single generation, the ability of a GM crop to survive vs a wild-type will be virtually identical. Evolution, of course, only acts over multiple generations at best. (Bacteria etc being the obvious exceptions.)
Imagine a corn-based disease that appears in the USA twenty years ago. It finds that some hybrids are susceptible and some are not as it spreads across the USA. And within hybrids, there may be some resistance from plant to plant, based on a heterogeneous genome diversity. Crops fail across the USA, but some small subset survives. Farmers have to hold back a certain percentage of their crop for next year's seed, as they always do, but because only the disease-resistant crops survived to maturity, their seed is already resistant to the blight. Assuming even that the blight allowed even damaged corn to survive to maturity, the seed planted that was not resistant would quickly succumb to the blight the next year, but the resistant variety would presumably be fine. In one generation, the best disease-resistant varieties of corn would become dominant. There would continue to be widespread shortages, but those would decline each year as more and more resistant corn reproduced and spread.
Now let's take the situation with one GM corn plant essentially reproduced nationwide as the only corn crop. Any disease that appears that does affect this plant will affect them all; they're the same. There is no heterogeneous diversity between them. The limits to the spread of the disease are based only on growing season, weather, geographical distribution, and time. Given the right conditions, an entire nation's crop might fail in a single growing season, and the rest would remain at risk for all subsequent growing seasons while the blight continued to exist.
Given the GM corn was not sterile, there might be storehouses of seed if the plants survived to maturity, even if all were at risk the next growing season. This would perhaps offset the devastation of the next season and buy time for a solution to be found. If the corn did not survive to maturity, no seed for the next growing season. If the seed were modified to render only sterile crops, then any subsequent seed would have to come from the manufacturer (as it already does in such cases). Their stockpiles would be based on the current genome or perhaps "next year's model," but with no guarantees that it would be resistant to the blight. Scientists could perform additional modifications to attempt to introduce resistance to the blight, and they might be successful, but those test plants would have to grow to maturity, reproduce, and then be bred again and again to build up a seed stock sufficient to supply the farmers with enough seed to replant. It would be years, assuming it could be done at all. In the meantime, corn (in this example) would be essentially extinct, except for any remaining heterogeneous domestic and wild varieties (which I presume would be prized).
Yes, this is stupid. However, it has little to do with the science of GM crops: rather the politics of a surplus.
Nonetheless, it goes hand-in-hand with the realities of GM foods.
This is conjecture, and quite a leap at that. Even if we accept that there will be only 1 supplier of seed in the US down the line, and even if we accept that wild-type grains will become completely extinct: if the end result is the proliferation of grains that are longer lasting, more land efficient, healthier and more robust then their wild-type cousins, I fail to see the problem.
One single genetic example of a plant is a single point of failure. I am an IT person, and this is my specialty. I am trained to spot the SPoF and avoid it at all costs. A GM crop is essentially one plant. And to make things worse, we are working rapidly towards plant cloning - GM and cloning to ensure that future GM plants aren't just nearly identical, but absolutely so.
