4 ms·

GMO corn has metabolism disturbances caused by the transformation process

39 points by randomname2 10y ago

sebleon 10y ago
Great article! Curious to see how GM industry will react, same-ness has been one of the big arguments against labelling GMO food.
- mgamache 10y ago
  They will criticize the research with hired 'thought leaders' and point to the 'overwhelming evidence' that proves GMOs and roundup is safe.
  - cmdrfred 10y ago
    I'm confused. Your argument appears to be that GMO corn and roundup is unsafe for corn? This paper doesn't have anything to do with human consumption.
    - mgamache 10y ago
      Let me be more specific: the question was "how will the GM industry will react" ‘substantially equivalent’ is a proxy for food safety and it's also a tricky standard. When interpreting this study's results the public and policy makers will look to academics: http://www.nytimes.com/2015/09/06/us/food-industry-enlisted-academics-in-gmo-lobbying-war-emails-show.html http://www.nytimes.com/2015/09/06/us/food-industry-enlisted-... Just by selectively funding academics that agree with them they can distort the debate.
      - cmdrfred 10y ago
        So do you have evidence it is unsafe or just are you simply against any organization that uses lobbyists? (Teachers unions, ACLU, Climate and Gay rights organizations, etc)
        mgamache 10y ago
        I didn't say anything about lobbyists. I do have an issue with supposedly unbiased experts being on a private payroll without full disclosure all-around. Would you be okay with a NY Times reporter getting funding for a story from Monsanto (without disclosure)?
        grzm 10y ago
        If I'm understanding you correctly, I think you might be blurring the lines here. A NYT reporter is a journalist, not an expert. They may use experts as sources for their stories. I agree that it would be a serious breach of ethics for a journalist to take money from Monsanto. It's not the same as an expert receiving funding from industry. That has it's own ethics issues, which I think are the ones you're getting at.
  - 7sigma 10y ago
    " point to the 'overwhelming evidence' that proves GMOs and roundup is safe" You can't prove with absolute certainty that any food is safe, only what the risks are. And yes there is a lot of real scientific and independent evidence that GMOs are no more risky than other foods. http://www.skepticalraptor.com/skepticalraptorblog.php/the-solid-gmo-scientific-consensus/ http://www.skepticalraptor.com/skepticalraptorblog.php/the-s...
cossatot 10y ago
Note for comments-first readers: this shows differences in corn metabolism, not in humans or other animals that have consumed the corn. However they reference studies where rats had worse health after eating GMO corn vs normal corn.
- makomk 10y ago
  In a sense this probably isn't terribly surprising; GM corn is known to have reduced yield due to disruption from the genetic modifications. The interesting part is that the composition of the resulting corn differs as a result of this in ways that weren't expected or previously known.
toufka 10y ago
The research compared an original strain to a modified strain, to the modified strain with roundup. It is unsurprising that the modified strain, that is producing an extra protein in high amounts will be under a heavier metabolic load than the same strain that is not producing that extra protein. It seems the metabolic load showed up in a few particular places that haven't obviously been investigated before, and now we can more carefully probe those differences now that the team did a thorough screen to find them. However, what the research did not do is compare the metabolic load in the modified strain to anything else. They did not compare it to an average corn strain, an 'heirloom' corn strain, a corn that is under cold/heat/viral or any other kind of environmental stress or bounty. Nor did they compare the corn metabolite levels to other foods. I suspect the difference in metabolic load between a strain +/- a particular resistance protein is likely less than the difference in metabolic load between various corn strains, much less the difference between fertilized/shaded/cold-conditioned corn, much less the original grass strain from which human-edible corn came from, much less from another food crop. The difference appears in the ratio of particular metabolites in the corn. And at the end of the day the difference in amounts of small molecules upon adding this metabolic stress is likely completely overwhelmed by the literal amount of material (ex. if you don't want that much of the metabolite, use 0.01% less corn. And if the corn is processed at all, this kind of difference becomes moot very quickly.) The result is not surprising and is framed in a particularly click/news-bait worthy way. The nice part of the research is that it did a lot of hard work to find the variables that now can be looked for in those above cross-wise comparisons without having to do the major hard work of screening an entire transcriptome for each comparison. But it does not in any way provide evidence for any danger to human health at all. Some math: The modified strain's largest difference in metabolites was a 28x increase in cadaverine (btw, it's pretty entertaining how many nitrogen-containing compounds have fantastic names because of their odor). According to [1] the difference in the amount of cadaverine between dried and canned corn is 5.5x (with the low cadaverine in dried corn mentioned as nutritionally deficient). And the total amount of cadavarine in fresh corn is ~ 10mg/100g which is ~ 0.01% by mass. Most of the other large changes in metabolites were changes of less than an order of magnitude. [1] http://www.sciencedirect.com/science/article/pii/S0308814611014129 http://www.sciencedirect.com/science/article/pii/S0308814611...
- 10y ago
Obi_Juan_Kenobi 10y ago
I can tell that no plant geneticists reviewed this paper, certainly no maize geneticists. The authors claim to use a 'near-isogenic' line for a control. > The varieties of maize used in this study were DKC 2678 Roundup-tolerant NK603 (Monsanto Corp., USA), and its nearest isogenic non-transgenic control DKC 2675 Yet no mention of how 'near' these lines are is made, nor is the seed provenance discussed. This is, frankly, absurd, as the Monsanto transgenic line began development decades ago. Presuming that the other inbred had been established at that point, there is a minimum of 20 years that these inbreds have been independently maintained. A proper experiment would have introgressed the EPSPS transgene into a known inbred. That is the only way you can ensure that you have a consistent genetic background, and is standard practice in the maize community. This is, almost without exception, reported in a manuscript. It is that important. To contextualize this, I've compared control groups of a particular inbred (e.g. B73, Mo17, A619) and seen substantial differences in RNAseq data, simply because it was seed stock from different labs. These are lines that have been shared within the past 10 years. The B73 inbred (from which the maize genome was/is sequenced) is notorious for being defined as 'a barrel of seed in Mike Freeling's lab'. Honesty, the sheer diversity of maize, along with wind pollination, complicated field conditions, and undergraduate help =P, make all maize inbreds a moving target. This is not a small detail of the paper; all the results rely on these lines actually being 'near-isogenic'. Any small differences between them can easily account for the observed differences. Hell, even after 3 or 4 rounds of introgression, you can often visually see differences between lines that aren't actually due to the trait in question; it's just background noise. Whatever your views on transgenic technology, I would not base any decision on this work.

39 points by randomname2 10y ago

Great article! Curious to see how GM industry will react, same-ness has been one of the big arguments against labelling GMO food.

mgamache 10y ago
They will criticize the research with hired 'thought leaders' and point to the 'overwhelming evidence' that proves GMOs and roundup is safe.
- cmdrfred 10y ago
  I'm confused. Your argument appears to be that GMO corn and roundup is unsafe for corn? This paper doesn't have anything to do with human consumption.
  - mgamache 10y ago
    Let me be more specific: the question was "how will the GM industry will react" ‘substantially equivalent’ is a proxy for food safety and it's also a tricky standard. When interpreting this study's results the public and policy makers will look to academics: http://www.nytimes.com/2015/09/06/us/food-industry-enlisted-academics-in-gmo-lobbying-war-emails-show.html http://www.nytimes.com/2015/09/06/us/food-industry-enlisted-... Just by selectively funding academics that agree with them they can distort the debate.
    - cmdrfred 10y ago
      So do you have evidence it is unsafe or just are you simply against any organization that uses lobbyists? (Teachers unions, ACLU, Climate and Gay rights organizations, etc)
      - mgamache 10y ago
        I didn't say anything about lobbyists. I do have an issue with supposedly unbiased experts being on a private payroll without full disclosure all-around. Would you be okay with a NY Times reporter getting funding for a story from Monsanto (without disclosure)?
        grzm 10y ago
        If I'm understanding you correctly, I think you might be blurring the lines here. A NYT reporter is a journalist, not an expert. They may use experts as sources for their stories. I agree that it would be a serious breach of ethics for a journalist to take money from Monsanto. It's not the same as an expert receiving funding from industry. That has it's own ethics issues, which I think are the ones you're getting at.
- 7sigma 10y ago
  " point to the 'overwhelming evidence' that proves GMOs and roundup is safe" You can't prove with absolute certainty that any food is safe, only what the risks are. And yes there is a lot of real scientific and independent evidence that GMOs are no more risky than other foods. http://www.skepticalraptor.com/skepticalraptorblog.php/the-solid-gmo-scientific-consensus/ http://www.skepticalraptor.com/skepticalraptorblog.php/the-s...

cossatot 10y ago

Note for comments-first readers: this shows differences in corn metabolism, not in humans or other animals that have consumed the corn. However they reference studies where rats had worse health after eating GMO corn vs normal corn.

makomk 10y ago
In a sense this probably isn't terribly surprising; GM corn is known to have reduced yield due to disruption from the genetic modifications. The interesting part is that the composition of the resulting corn differs as a result of this in ways that weren't expected or previously known.

toufka 10y ago

The research compared an original strain to a modified strain, to the modified strain with roundup. It is unsurprising that the modified strain, that is producing an extra protein in high amounts will be under a heavier metabolic load than the same strain that is not producing that extra protein. It seems the metabolic load showed up in a few particular places that haven't obviously been investigated before, and now we can more carefully probe those differences now that the team did a thorough screen to find them. However, what the research did not do is compare the metabolic load in the modified strain to anything else. They did not compare it to an average corn strain, an 'heirloom' corn strain, a corn that is under cold/heat/viral or any other kind of environmental stress or bounty. Nor did they compare the corn metabolite levels to other foods. I suspect the difference in metabolic load between a strain +/- a particular resistance protein is likely less than the difference in metabolic load between various corn strains, much less the difference between fertilized/shaded/cold-conditioned corn, much less the original grass strain from which human-edible corn came from, much less from another food crop. The difference appears in the ratio of particular metabolites in the corn. And at the end of the day the difference in amounts of small molecules upon adding this metabolic stress is likely completely overwhelmed by the literal amount of material (ex. if you don't want that much of the metabolite, use 0.01% less corn. And if the corn is processed at all, this kind of difference becomes moot very quickly.) The result is not surprising and is framed in a particularly click/news-bait worthy way. The nice part of the research is that it did a lot of hard work to find the variables that now can be looked for in those above cross-wise comparisons without having to do the major hard work of screening an entire transcriptome for each comparison. But it does not in any way provide evidence for any danger to human health at all. Some math: The modified strain's largest difference in metabolites was a 28x increase in cadaverine (btw, it's pretty entertaining how many nitrogen-containing compounds have fantastic names because of their odor). According to [1] the difference in the amount of cadaverine between dried and canned corn is 5.5x (with the low cadaverine in dried corn mentioned as nutritionally deficient). And the total amount of cadavarine in fresh corn is ~ 10mg/100g which is ~ 0.01% by mass. Most of the other large changes in metabolites were changes of less than an order of magnitude. [1] http://www.sciencedirect.com/science/article/pii/S0308814611014129 http://www.sciencedirect.com/science/article/pii/S0308814611...

10y ago

Obi_Juan_Kenobi 10y ago

I can tell that no plant geneticists reviewed this paper, certainly no maize geneticists. The authors claim to use a 'near-isogenic' line for a control. > The varieties of maize used in this study were DKC 2678 Roundup-tolerant NK603 (Monsanto Corp., USA), and its nearest isogenic non-transgenic control DKC 2675 Yet no mention of how 'near' these lines are is made, nor is the seed provenance discussed. This is, frankly, absurd, as the Monsanto transgenic line began development decades ago. Presuming that the other inbred had been established at that point, there is a minimum of 20 years that these inbreds have been independently maintained. A proper experiment would have introgressed the EPSPS transgene into a known inbred. That is the only way you can ensure that you have a consistent genetic background, and is standard practice in the maize community. This is, almost without exception, reported in a manuscript. It is that important. To contextualize this, I've compared control groups of a particular inbred (e.g. B73, Mo17, A619) and seen substantial differences in RNAseq data, simply because it was seed stock from different labs. These are lines that have been shared within the past 10 years. The B73 inbred (from which the maize genome was/is sequenced) is notorious for being defined as 'a barrel of seed in Mike Freeling's lab'. Honesty, the sheer diversity of maize, along with wind pollination, complicated field conditions, and undergraduate help =P, make all maize inbreds a moving target. This is not a small detail of the paper; all the results rely on these lines actually being 'near-isogenic'. Any small differences between them can easily account for the observed differences. Hell, even after 3 or 4 rounds of introgression, you can often visually see differences between lines that aren't actually due to the trait in question; it's just background noise. Whatever your views on transgenic technology, I would not base any decision on this work.