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Genetically Engineered Crops—What, How and Why

The views expressed are those of the author and are not necessarily those of Scientific American.


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By the turn of the century, the number of people on Earth is expected to increase from the current 6.7 billion to 10 billion. How can we feed the growing population without further degrading the environment?

Because the amount of land and water is limited, it is no longer possible to simply expand farmland to produce more food. Instead, increased food production must largely take place on the same land area, while using less water. Compounding the challenges facing agricultural production are the predicted effects of climate change: flooding in some places, droughts in others and new pests and disease outbreaks.

Thus, an important goal for the US and other countries is to develop more effective land and water use policies, improved integrated pest management approaches, reduce harmful inputs, and create new crop varieties tolerant of diverse stresses.

These strategies must be evaluated in light of their environmental, economic, and social impacts—the three pillars of sustainable agriculture (Committee on the Impact of Biotechnology on Farm-Level Economics and Sustainability and National Research Council 2010).

WHAT ARE GENETICALLY ENGINEERED CROPS?

Genetic engineering differs from conventional methods of genetic modification in two major ways: (1) genetic engineering introduces one or a few well-characterized genes into a plant species and (2) genetic engineering can introduce genes from any species into a plant. In contrast, most conventional methods of genetic modification used to create new varieties (e.g., artificial selection, forced interspecific transfer, random mutagenesis, marker-assisted selection, and grafting of two species, etc.) introduce many uncharacterized genes into the same species. Conventional modification can in some cases transfer genes between species, such as wheat and rye or barley and rye.

In 2008, the most recent year for which statistics are available, 30 genetically engineered crops were grown on almost 300 million acres in 25 countries (nearly the size of the state of Alaska), 15 of which were developing countries (James 2009). By 2015, 120 genetically engineered crops (including potato and rice) are expected to be cultivated worldwide (Stein and Rodriguez-Cerezo 2009). Half of the increase will be crops designed for domestic markets from national technology providers in Asia and Latin America.

SAFETY ASSESSMENT OF GENETICALLY ENGINEERED CROPS

There is broad scientific consensus that genetically engineered crops currently on the market are safe to eat. After 14 years of cultivation and a cumulative total of 2 billion acres planted, no adverse health or environmental effects have resulted from commercialization of genetically engineered crops (Board on Agriculture and Natural Resources, Committee on Environmental Impacts Associated with Commercialization of Transgenic Plants, National Research Council and Division on Earth and Life Studies 2002). Both the U.S. National Research Council and the Joint Research Centre (the European Union’s scientific and technical research laboratory and an integral part of the European Commission) have concluded that there is a comprehensive body of knowledge that adequately addresses the food safety issue of genetically engineered crops (Committee on Identifying and Assessing Unintended Effects of Genetically Engineered Foods on Human Health and National Research Council 2004; European Commission Joint Research Centre 2008).

These and other recent reports conclude that the processes of genetic engineering and conventional breeding are no different in terms of unintended consequences to human health and the environment (European Commission Directorate-General for Research and Innovation 2010). This is not to say that every new variety will be as benign as the crops currently on the market. This is because each new plant variety (whether it is developed through genetic engineering or conventional approaches of genetic modification) carries a risk of unintended consequences. Whereas each new genetically engineered crop variety is assessed on a case-bycase basis by three governmental agencies, conventional crops are not regulated by these agencies.

Still, to date, compounds with harmful effects on humans or animals have been documented only in foods developed through conventional breeding approaches. For example, conventional breeders selected a celery variety with relatively high amounts of psoralens to deter insect predators that damage the plant. Some farm workers who harvested such celery developed a severe skin rash—an unintended consequence of this breeding strategy (Committee on Identifying and Assessing Unintended Effects of Genetically Engineered Foods on Human Health and National Research Council 2004).

INSECT-RESISTANT CROPS

“A truly extraordinary variety of alternatives to the chemical control of insects is available. Some are already in use and have achieved brilliant success. Others are in the stage of laboratory testing. Still others are little more than ideas in the minds of imaginative scientists, waiting for the opportunity to put them to the test. All have this in common: they are biological solutions, based on the understanding of the living organisms they seek to control and of the whole fabric of life to which these organisms belong. Specialists representing various areas of the vast field of biology are contributing—entomologists, pathologists, geneticists, physiologists, biochemists, ecologists—all pouring their knowledge and their creative inspirations into the formation of a new science of biotic controls.” (Carson 1962, p. 278)

In the 1960s, the biologist Rachel Carson brought the harmful environmental and human health impacts resulting from overuse or misuse of some insecticides to the attention of the wider public. Even today, thousands of pesticide poisonings are reported each year (1200 illnesses related to pesticide poisoning in California, 300,000 pesticide-related deaths globally).

This is one reason some of the first genetically engineered crops were designed to reduce reliance on sprays of broad-spectrum insecticides for pest control. Corn and cotton have been genetically engineered to produce proteins from the soil bacteria Bacillus thuringiensis (Bt) that kill some key caterpillar and beetle pests of these crops. Bt toxins cause little or no harm to most beneficial insects, wildlife, and people (Mendelsohn et al. 2003).

Bt toxins kill susceptible insects when they eat Bt crops. This means that Bt crops are especially useful for controlling pests that feed inside plants and that cannot be killed readily by sprays, such as the European corn borer (Ostrinia nubilalis), which bores into stems, and the pink bollworm (Pectinophora gossypiella), which bores into bolls of cotton.

First commercialized in 1996, Bt crops are the second most widely planted type of transgenic crop. Bt toxins in sprayable formulations were used for insect control long before Bt crops were developed and are still used extensively by organic growers and others. The long-term history of the use of Bt sprays allowed the Environmental Protection Agency and the Food and Drug Administration to consider decades of human exposure in assessing human safety before approving Bt crops for commercial use. In addition, numerous toxicity and allergenicity tests were conducted on many different kinds of naturally occurring Bt toxins. These tests and the history of spraying Bt toxins on food crops led to the conclusion that Bt corn is as safe as its conventional counterpart and therefore would not adversely affect human and animal health or the environment (European Food Safety Authority 2004).

Planting of Bt crops has resulted in the application of fewer pounds of chemical insecticides and thereby has provided environmental and economic benefits that are key to sustainable agricultural production. In Arizona, where an integrated pest management program for Bt cotton continues to be effective, growers reduced insecticide use by 70% and saved .$200 million from 1996 to 2008 (Naranjo and Ellsworth 2009).

A recent study indicates that the economic benefits resulting from Bt corn are not limited to growers of the genetically engineered crop (Hutchison et al. 2010). In 2009, Bt corn was planted on .22.2 million hectares, constituting 63% of the U.S. crop. For growers of corn in Illinois, Minnesota, and Wisconsin, cumulative benefits over 14 years are an estimated $3.2 billion. Importantly, $2.4 billion of this total benefit accrued to non-Bt corn (Hutchison et al. 2010). This is because area-wide suppression of the primary pest, O. nubilalis, reduced damage to non-Bt corn. Comparable estimates for Iowa and Nebraska are $3.6 billion in total, with $1.9 billion for non-Bt corn. These data confirm the trend seen in some earlier studies indicating that communal benefits are sometimes associated with planting of Bt crops (Carriere et al. 2003; Wu et al. 2008; Tabashnik 2010).

Planting of Bt crops has also supported another important goal of sustainable agriculture: increased biological diversity. An analysis of 42 field experiments indicates that nontarget invertebrates (i.e., insects, spiders, mites, and related species that are not pests targeted by Bt crops) were more abundant in Bt cotton and Bt corn fields than in conventional fields managed with insecticides (Marvier et al. 2007). The conclusion that growing Bt crops promotes biodiversity assumes a baseline condition of insecticide treatments, which applies to 23% of corn acreage and 71% of cotton acreage in the United States in 2005 (Marvier et al. 2007).

Benefits of Bt crops have also been well-documented in less-developed countries. For example, Chinese and Indian farmers growing genetically engineered cotton or rice were able to dramatically reduce their use of insecticides (Huang et al. 2002, 2005; Qaim and Zilberman 2003; Bennett et al. 2006). In a study of precommercialization use of genetically engineered rice in China, these reductions were accompanied by a decrease in insecticide-related injuries (Huang et al. 2005).

Although Bt cotton is effective in reducing cotton bollworm outbreaks in China other pests that are not killed by Bt cotton are increasingly problematic (Wu Review 13et al. 2008; Lu et al. 2010). These results confirm the need to integrate Bt crops with other pest control tactics (Tabashnik et al.
2010). In Arizona, such an integrated pest management (IPM) approach has been implemented (Naranjo and Ellsworth 2009). In Arizona’s cotton IPM system, key pests not controlled by Bt cotton are managed with limited use of narrow-spectrum insecticides that promote conservation of beneficial insects (Naranjo and Ellsworth 2009). Mirids such as the Lygus bug (Lygus hesperus) are controlled with a feeding inhibitor, and the sweet potato whitefly (Bemisia tabaci) is controlled with insect growth regulators (Naranjo and Ellsworth 2009).

One limitation of using any insecticide, whether it is organic, synthetic, or genetically engineered, is that insects can evolve resistance to it. For example, one crop pest, the diamondback moth (Plutella xylostella), has evolved resistance to Bt toxins. This resistance occurred in response to repeated sprays of Bt toxins to control this pest on conventional (nongenetically engineered) vegetable crops (Tabashnik 1994).

These results underscore a well-known paradigm in agriculture: pest resistance will evolve is the selection pressure is high. Why then, have most Bt crops remained effective against most pests for more than a decade (Tabashnik et al. 2008; Carriere et al. 2010)? The answer is genetic diversity. The inclusion in farmers fields of crop plants that do not make Bt toxins has helped to delay evolution of pest resistance to Bt crops (Carriere et al. 2010).

In cases where insect resistance to Bt crops has evolved, one or more conditions of this crop diversity strategy have not been met. For example, failure to provide adequate refuges of non-Bt cotton appears to have hastened resistance of pink bollworm in India (Bagla 2010). In contrast, Arizona cotton growers complied with this strategy from 1996 to 2005, and no increase in pink bollworm resistance occurred (Tabashnik et al. 2010).

In the United States, Bt cotton producing only Cry1Ac is no longer registered and has been replaced primarily by Bt cotton that produces two toxins (Carriere et al. 2010). More generally, most newer cultivars of Bt cotton and Bt corn produce two or more toxins. These multitoxin Bt crops are designed to help delay resistance an to kill a broader spectrum of insect pests (Carriere et al. 2010). For example, a new type of Bt corn produces five Bt toxins—three that kill caterpillars and two that kill beetles (Dow Agrosciences 2009).

Despite the success of the crop diversity strategy in delaying insect resistance to Bt crops, this approach has limitations, including the fact that not all farmers will comply. An alternative strategy entails release of sterile insects to mate with resistant insects (Tabashnik et al. 2010). Incorporation of this strategy in a multi-tactic eradication program in Arizona from 2006 to 2009 reduced pink bollworm abundance by 99%, while eliminating insecticide sprays against this pest. The success of such creative multidisciplinary integrated approaches, involving entomologists, geneticists, physiologists, biochemists, and ecologists, provides a roadmap for the future of agricultural production and attests to the foresight of Rachel Carson.

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Pamela Ronald About the Author: Pamela Ronald is a Professor at the University of California, Davis where she studies how genes affect the plant’s response to environmental stress and disease. She is co-author of ‘Tomorrow’s Table: Organic Farming, Genetics and the Future of Food”. Find her on the web at http://cropgeneticsinnovation.org/. Follow on Twitter @pcronald.

The views expressed are those of the author and are not necessarily those of Scientific American.






Comments 46 Comments

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  1. 1. all4kindness2all 6:14 pm 08/11/2011

    Really informative. I had only the vaguest idea of what it meant to “genetically altered” before reading this. Thank you. Your clarity on the topic is extraordinary.

    Link to this
  2. 2. KPH346 3:27 pm 08/12/2011

    This is the conundrum. We either produce more food or less people.
    Which people do we produce less of; and how will we do it? Look for a population explosion in China/Asia where the predilection toward obedience to the state is waning and the people become relatively affluent. In Africa we may see a virtual depopulation in the Sub-Saharan continent because of famine, disease and warfare.
    The Americas are seeing a shift in demographics but so far sustainable growth.
    I see the problem as too many people but too many people trying to live on too small an area.
    Maybe we could make more land arable (bad speller, I know).
    Is it true that something as simple as the absorbent material in Pampers of all things can be implanted in drought/desert ground. The result is land that retains what little moisture it receives. Enough to grow crops.
    People could spread out.
    I know I’m an unlettered man, but I’d like to ask you more erudite types if this is possible
    Floating icebergs down for water is intriguing but I wonder what that would do to ecosystems and salinity issues.

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  3. 3. NonlinearEd 7:37 pm 08/12/2011

    I find no mention of the “Roundup Ready” glyophosphate(sp)resistant GMOs produced my Monsanto. Where, in lieu of introducing say, Bt producing, drought resistance, or other beneficial genes, Monsanto just made the plant immune to the toxin when sprayed with their signature herbicide.
    Consequently, the glyophosphate is taken up by the plant and consumed. Principally corn and soybeans at present but alfalfa is now allowed. All three are used as animal feed. In addition, super-weeds are now a documented threat due to higher than normal crop field spraying with Roundup. Runoff is also an issue.
    In addition, legislation is in place which allows Monsanto to claim and destroy any non GMO crop which is cross contaminated by their pollen. IOW, your natural alfalfa crop is pollinated by their alfalfa crop across the road. They will sue you and win.
    Oh yeah. The farmer is also prohibited from planting seed saved from a crop.
    There is obviously much to be hammered out before GMO crops are a safe as they are presumed to be.

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  4. 4. RussellHJoyce 1:39 am 08/13/2011

    What ever you say or how well you think you make your argument for the justification of genetically altered food in my opinion an extremely foolhardy in that we can not predict genetic mutations. We may have mapped some of the DNA code but not all and we sure an heck do not understand it’s complexity.
    Keep a sample of all the modified seeds in a freezer and promote organic farming. So the stock of the seed barons will go down, at least our DNA is safe for future generations.
    Beware: When ever you change any system by any means you always generate chaos.

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  5. 5. rmstallman 2:22 am 08/18/2011

    This article addresses the safety of certain GMO crops. “Roundup
    ready” GMO crops raise a somewhat different safety issue about the
    weed-killer glyphosate.

    However, GMO crops cause other problems not addressed here. For
    instance, the dependence of agriculture on a large company, and the
    requirement for farmers to purchase patented seed every year. Since
    maize is wind-polinated, GM maize presents the problem of
    contamination of other farms’ crops with patented pollen. The
    arguments about safety in this article don’t even start to show that
    those problems are acceptable.

    Rather than putting effort into GMOs, perhaps society should put it
    into encouraging and facilitating contraception and abortion around
    the world. With luck, the number of human mouths to feed will not
    rise so high. We can also put effort into encouraging healthier
    eating with less meat, and greatly reduce the amount of land, water
    and fertilizer needed per mouth.

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  6. 6. MBendzela 3:46 am 08/18/2011

    Pamela Ronald’s book was instrumental in helping me change my mind about GM crops. But she as usual she overstates the case against “pesticides”:

    “Even today, thousands of pesticide poisonings are reported each year (300,000 deaths globally, 1200 each year in California alone).”

    This is shockingly inaccurate.

    From California’s Department of Pesticide Regulation:

    “In California, 157 suspected pesticide fatalities were reported to the pesticide illness registry between 1982 and 2007.” That’s about ten per year, and they are not caused by consumers eating foods that have been sprayed.

    http://www.cdpr.ca.gov/docs/whs/memo/hsm09009.pdf

    It is simply impossible that there were 1,200 pesticide deaths in California in one year, as Ronald indicates.

    She also fails to mention that pesticides poisonings are overwhelmingly the results of attempted suicides. Most others have to do with accidents involving children from illegally stored pesticides. From the above memo:

    “Of the 29 ChE cases, there were 7 occupational poisonings, including 2 accidental ingestions. Of the 22 non-occupational ingestions, there were 19 suicides. The remaining cases, described in detail in Appendix Table 1, included an accidental childhood ingestion from an unsecured container (Case #1982-1530), an ingestion with insufficient information to determine whether it was suicidal, accidental (Case # 1982-124), and 1 ingestion with insufficient information to determine whether it was suicidal, accidental or deliberate poisoning by a second party.”

    Not only that:

    “Sixty-three cases were classified as unrelated to pesticide exposure or with insufficient information to classify. These included 22 aviation accidents (34.9%), 31 cases involving myocardial infarction, stroke or other unrelated medical condition (48.4%), 4 tractor accidents (6.3%), 5 cases with incomplete information (7.8%) and 1 murder victim whose murderer then used a pesticide to commit suicide.”

    This is a pattern I have noted with Ronald before. She likes to leave the impression that consumers are being poisoned by their food even though there is absolutely no evidence that this is happening.

    I don’t know why someone as articulate and intelligent as Ronald could be so irrational around the issue of pesticides use. They are our friends when used properly. I feel the same way about GM products.

    The most compelling reason for the farmer to scale back pesticides use is that they are expensive and time-consuming to apply.

    Most of us small farmers will probably never get to use crops that have been genetically altered to resist insects due to their cost: They are scaled for factory farms, not small vegetable operations like ours here in Maine. So we will continue to use pesticides–safely.

    Therefore, I resent the vilification Ronald places upon pesticides because it places yet another undo burden upon the really small farmer. I’m a licensed pesticides applicator and often a properly-applied pesticide means the difference between having a crop and not having a crop.

    Ronald does no one any service by spreading misinformation about pesticides.

    Link to this
  7. 7. MBendzela 4:42 pm 08/18/2011

    Pamela was kind enough to write to say that the line in question was a mistake. She meant not that 1,200 deaths occurred in California but that 1,200 poisonings occurred. I feel a little silly and apologize for the tone of my response.

    Remember that those of us who are very small farmers will probably not benefit from genetically engineered seeds and crops, and most of us are not interested in “organic” certification. This means we will continue to use pesticides as we see fit. The “organic” cult will continue to put us on the defensive with their outrageous claims about pesticides (see the Environmental Working Group and their appallingly inaccurate “Dirty Dozen” list).

    I apologize if I seemed to put Ms. Ronald in the latter camp.

    Link to this
  8. 8. Incoerências « Mario A. Lira Junior 12:42 pm 08/28/2011

    [...] assuntos que não tenham pelo menos um semblante de ligação com as disciplinas, mas estava lendo esta matéria no blog da Scientific American, e não consegui me conter. Em síntese, o autor discute o grau de [...]

    Link to this
  9. 9. GMKnow 4:13 pm 08/30/2011

    Ms. Ronald receives grant monies from agriculture biotech companies like Monsanto. Her views, science and research aside, are commercially motivated.

    The one question she will not address, that all the GMO companies avoid, is why GMOs were silently slipped into the American food chain without warning, labels or human health studies? In fact, a now famous quote from a Monsanto representative pretty much sums up the argument, to wit: “If you put a label on genetically engineered food you might as well put a skull and crossbones on it.” – Norman Braksick

    GMOs have been hidden from the American eating public for 15 years. It’s a fraud perpetrated on eaters everywhere courtesy of biotech companies, multinational food companies and compromised Federal regulators. With no GMO labels, “there are no recorded instances of disease,” goes the common biotech defense. Meanwhile, over the last 15 years the US has recorded unprecedented levels of disease including cancer, diabetes, asthma, Alzheimer and so on. No other developed nation has seen such a drastic increase, and especially those who have restricted GMOs release in their country’s food supply or require clear GMO labeling.

    I’d like to ask Ms. Ronald if she believes food choice is right or a privilege. Clearly there are differences between GMO plants and natural varieties. GMO DNA is added to impart death defying and killing qualities: that a plant may withstand being sprayed with powerful weed killers plus contain a built-in bug killer. As for me, I prefer foods that nourish. Foods with built-in pesticide in every cell I choose to avoid as I’m sure most reasonable persons would do. The fact the Biotech/GMO advocates deny us the right to know about GMOS casts a serious doubt on their objectivity and the validity of their so-called science.

    Personally, I’m quite angry about playing Ms. Ronald’s et al human GMO test subject.

    Link to this
  10. 10. Genetically Engineered Crops—What, How and Why « Wellness-cc 5:51 pm 10/7/2011

    [...] the rest at http://blogs.scientificamerican.com/guest-blog/2011/08/11/genetically-engineered-crops/ Rate this: Share this:TwitterFacebookLike this:LikeBe the first to like this post. Categories: [...]

    Link to this
  11. 11. seo experts academy review 3:27 am 10/17/2011

    I have read so many articles about genetic engineering.And I think this is one of the best I read.. wonderful!

    Link to this
  12. 12. seo experts academy review 3:29 am 10/17/2011

    genetic engineering is a practical solution to our increasing demands of food.
    http://www.seoexpertsacademy.net/seo-experts-academy-review

    Link to this
  13. 13. msousa 7:37 pm 12/6/2011

    To GMKnow:
    I respect your choice of not eating GE crops and you can in fact choose to eat “certified organic” if that is what you prefer (and I often do). I also do not think it is unreasonable to ask for food containing GE crops to be so labeled.

    However you write: “Meanwhile, over the last 15 years the US has recorded unprecedented levels of disease including cancer, diabetes, asthma, Alzheimer and so on…”

    As for cancer: according to the FDA, the first GE crops were introduced in 1996. Copied below are the cancer incidence rates (delay adjusted) from 1996 to 2008 (last year available) as reported by the Surveillance Epidemiology and End Results (SEER) center of the National Cancer Institute:

    1996 479.38
    1997 486.78
    1998 488.44
    1999 491.04
    2000 486.59
    2001 490.24
    2002 487.99
    2003 475.41
    2004 475.97
    2005 470.92
    2006 473.74
    2007 478.96
    2008 473.95

    So lets not exaggerate….

    Not every GE crop is created equal. There is certainly room to discuss regulations and curb the power that single companies (like Monsanto) would have over the food supply. But it is important to have rational discussions based on scientific data.

    By the way, I am a scientist but do not receive any grant money or any other compensation, direct or indirect, from any company.

    Link to this
  14. 14. Julia108 2:39 pm 12/10/2011

    I found this article on GM crops very misleading. According the numerous independent studies and per Dr. Don Huber:
    - herbicides and pesticides immobilize specific nutrients; GMOs are deficient in important minerals such as iron and zinc.
    - Glyphosates applied to GM crops, damage the soil microbiology, kill bees and render soils useless for decades.
    - Ingesting GMOs destroy the healthy gut flora in our bodies and has led to increased botulism in cattle consuming GM crops.
    - GMO crops need far more pesticides applied then conventional crops, thus harming our environment and our health.
    The lack of truth in articles promoting GMOs is very misleading to the public and thus skewing the real impact GMOs have on our food supply.
    - If GMO alfalfa contaminates organic alfalfa, our organic industry will be destroyed and the destruction of our health will soon follow.
    Greedy corporations like Monsanto will cost the public their lives and livelihoods. Don’t be fooled by the studies that promote GMOs, they are funded and coerced by Monsanto.

    Link to this
  15. 15. Collide-a-scape » Blog Archive » Collide-a-scape >> Pay No Mind to These Harassed Scientists 10:39 am 04/13/2012

    [...] the UK.) This despite abundant evidence that worrisome impacts to public health and ecosystems are unfounded, notwithstanding hysterical media reports to the [...]

    Link to this
  16. 16. GMO opponents are the global warming denialists of the left 10:13 pm 10/1/2012

    [...] Ronald, a UC-Davis plant geneticist, pointed out last year in Scientific American: “There is broad scientific consensus that genetically [...]

    Link to this
  17. 17. Straus Family Creamery Issues New Packaging to Support Prop 37 and GMO Labeling | Sustainable Food 6:16 pm 10/9/2012

    [...] debate since Calgene introduced the first GM food – the Flavr Savr tomato – in 1994. Supporters say GM foods are a solution to global overpopulation and decreasing land resources, while opponents argue that GM foods pose risks to the environment and human health. Nevertheless, [...]

    Link to this
  18. 18. December 2012: The Debate on GMOs 4:07 pm 11/26/2012

    [...] Ronald, a UC-Davis plant geneticist, phrased it last year inScientific American: “There is broad scientific consensus that genetically engineered crops currently on the market [...]

    Link to this
  19. 19. Belief and Personal Choice -- a Nadder! 12:49 am 11/27/2012

    [...] believe that GMOs are safe wouldn’t have much weight, but if I said that in academia there is broad consensus on safety, perhaps that might be more [...]

    Link to this
  20. 20. New Trend in Biotechnology: Genetically Engineered Crops | The Professional Field of Biotechnology 12:13 pm 11/29/2012

    [...] approaches, reduce harmful inputs, and create new crop varieties tolerant of diverse stresses”. http://blogs.scientificamerican.com/guest-blog/2011/08/11/genetically-engineered-crops/ Currently this trend is growing very rapidly and has spread too many countries. Many people are [...]

    Link to this
  21. 21. Bt « Biology Fortified, Inc. 1:22 pm 12/28/2012

    [...] Genetically Engineered Crops—What, How and Why – Scientific American [...]

    Link to this
  22. 22. An Environmentalist’s Public Reversal | MIND BLOWN 8:22 pm 01/7/2013

    [...] all the more effectively because he knows the fallacious anti-GMO arguments so intimately. As Pamela Ronald observed in Scientific American last year, “There is broad scientific consensus that genetically [...]

    Link to this
  23. 23. Bt | Anastasia Bodnar 11:07 pm 01/20/2013

    [...] Genetically Engineered Crops—What, How and Why – Scientific American [...]

    Link to this
  24. 24. In defence of Mark Lynas: 5 Green Herrings and the Amish « SkeptEco 9:59 am 02/10/2013

    [...] problem, not because it represents ‘progress’ ” he says, and I agree and I think most of the scientists who point to evidence that does support the usefulness of GE would also agree: support for a technology should be based on whether it does actually solve [...]

    Link to this
  25. 25. GMO Health Risks: What The Scientific Evidence Says 10:01 pm 03/30/2013

    [...] are safe to eat,” Pamela Ronald, a Univeristy of California at Davis professor, wrote for Scientific American [4] in 2011. But the American Academy of Environmental Medicine [5] has warned of “serious [...]

    Link to this
  26. 26. Genetically Engineered Crops – What, How and Why | Science on the Land 4:49 pm 04/8/2013

    [...] Here’s an article by Pamela Ronald in Scientific American, telling us why she believes that genetically modified (GM, also called genetically engineered) crops are what the world needs to feed our growing population. [...]

    Link to this
  27. 27. GMO Free Connecticut spouts myths and misinformation at library talk 10:16 pm 04/14/2013

    [...] organization has indicated that GMO foods pose no harm of any kind. Here is a good review in Scientific American by Pamela Ronald. And the position of theAmerican Association for the Advancement of Science is [...]

    Link to this
  28. 28. Kenya just banned GMO food | Farm Bualada 7:54 pm 05/15/2013

    [...] market are safe to eat,” Pamela Ronald, a Univeristy of California at Davis professor, wrote for Scientific American in 2011. But the American Academy of Environmental Medicine has warned of “serious health [...]

    Link to this
  29. 29. Allergic to Science-Proteins and Allergens in Our Genetically Engineered Food | Florida State Tribune 12:24 pm 05/30/2013

    [...] also worth noting as Pamela Ronald did in this space two years ago: There is broad scientific consensus that genetically engineered crops [...]

    Link to this
  30. 30. Connecticut Passes GMO Labeling Law | Smart News 1:51 pm 06/5/2013

    [...] little, if any, science has proven GMOs to be dangerous for people’s health. Genetics professor Pamela Ronald wrote in Scientific American in 2011, “There is broad scientific consensus that genetically engineered crops currently on the market [...]

    Link to this
  31. 31. Will a failure to consider GM hold back sustainable fish farming | marketspace 1:33 am 06/12/2013

    [...] company’s commitment to transparency, but labelling could also stigmatise GMOs, despite the broad scientific consensus in the US that the genetically engineered crops currently on the market are safe to [...]

    Link to this
  32. 32. swordofscience | What You Eat – GMO Labeling 11:26 pm 06/20/2013

    [...] to make an informed decision at the supermarket. The research on this point, however, is almost universally supportive of the safety of these crops; as reported by the National Research Council, after “14 years of cultivation and a [...]

    Link to this
  33. 33. Whole Foods: Misguided about GMOs 3:43 pm 06/26/2013

    [...] that the genetically engineered crops now on the market are safe to eat. I took the phrase from a blog by plant scientist Pamela Ronald (who I’ve met, and respect) that appeared in 2011 in Scientific [...]

    Link to this
  34. 34. Belief and Personal Choice | Fail Blue Dot 6:37 am 08/14/2013

    [...] believe that GMOs are safe wouldn’t have much weight, but if I said that in academia there is broad consensus on safety, perhaps that might be more [...]

    Link to this
  35. 35. Ein Gentechnik-Aktivist entschuldigt sich! › Detritus › SciLogs - Wissenschaftsblogs 9:27 am 10/7/2013

    [...] bieten bereits heute verfügbare Merkmale viele Umweltvorteile, vor allem eine Reduzierung der benötigten Ressourcen. Lynas sieht sie als Werkzeug, um das [...]

    Link to this
  36. 36. GMOs and the Liberal War on Science - OPaM 9:04 am 10/29/2013

    [...] conventional non-genetically modified plant.Or, as Pamela Ronald, a UC-Davis plant geneticist, wrote in Scientific American: “There is broad scientific consensus that genetically engineered crops [...]

    Link to this
  37. 37. The Science Behind Hawaii's GMO Bill 113 | ChefEnvy 8:56 am 11/1/2013

    [...] modified (GM) crops the Agrochemical industry and its academic supporters claim that a scientific consensus exists about their safety. Proponents also claim that GMOs may be vital for Hawaii farmers in case a [...]

    Link to this
  38. 38. McDonald’s GMO dilemma: why fries are causing such a fuss | Truth About Trade & Technology 12:16 pm 12/4/2013

    [...] regulatory experts”. If that’s so, the decision should be straightforward, given the broad scientific consensus in the US that the genetically engineered crops currently on the market are safe to [...]

    Link to this
  39. 39. McDonalds GMO dilemma, why fries are causing such a fuss | marketspace 3:48 am 12/5/2013

    [...] regulatory experts”. If that’s so, the decision should be straightforward, given the broad scientific consensus in the US that the genetically engineered crops currently on the market are safe to [...]

    Link to this
  40. 40. McDonald’s GMO dilemma: why fries are causing such a fuss : Dr. Leonard Coldwell.com 8:25 am 12/18/2013

    [...] regulatory experts”. If that’s so, the decision should be straightforward, given the broad scientific consensus in the US that the genetically engineered crops currently on the market are safe to [...]

    Link to this
  41. 41. Jane Goodall’s Troubling Error-filled New Book ” Seeds of Hope” , Plagiarized And With Quotes From Wikipedia | Ann Novek--With the Sky as the Ceiling and the Heart Outdoors 11:14 pm 03/27/2014

    [...] in Scientific American in 2011, UC Davis plant geneticist Pamela Ronald summed up the “broad scientific consensus that genetically engineered crops currently on the market are [...]

    Link to this
  42. 42. tina66 11:18 pm 04/1/2014

    Hi there to all, it’s really a nice for me to pay a visit this web site, it includes important Information.bathmate

    Link to this
  43. 43. Science108 9:36 am 04/22/2014

    I used to think that Monsanto propagandist Pamela Ronald was fooling Scientific American, but now I realize that Scientific American has been fooling us all. You yourself have become an agent of misinformation on GMOs.

    Your pro-GMO propaganda efforts all take the same form:

    1. Choose an “objective” scientist who is not directly associated with the company but is beholden to the industry;
    2. Start with the standard fear-mongering about world population growth and food supply;
    3. Grab a few convenient supporting facts and misrepresent their true weight with confident bravado;
    4. Claim that only GMO has chance of providing food for a growing world if only opponents would get out of the way;
    5. Suggest that anyone who has a contrary fact or opinion just isn’t smart enough to understand.

    Monsanto is sinking fast and SA may well go down with the rotten ship.

    It’s been nice knowing you.

    Link to this
  44. 44. GMO opponents are the left's version of global warming deniers 6:47 pm 05/19/2014

    [...] Ronald, a UC-Davis plant geneticist, pointed out last year in Scientific American: “There is broad scientific consensus that genetically [...]

    Link to this
  45. 45. Democrats Have A Problem With Science, Too — The Today Online 2:19 am 06/3/2014

    [...] foods to be no riskier than foods resulting from conventional breeding. Eating a GM tomato is just as safe as eating a non-GM tomato. The AAAS therefore opposes GMO labeling because it could “mislead and [...]

    Link to this
  46. 46. Genetically Engineered Food…Friend or Foe? | The Inside Out Gym 12:16 am 06/22/2014

    [...] http://blogs.scientificamerican.com/guest-blog/2011/08/11/genetically-engineered-crops/ [...]

    Link to this

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