Genetically Modified Foods (GM foods)
Updated April 2003

This is a very controversial area of plant biology. For years now, we have been able to take genes from other organisms and specifically place them in plants. These plants are referred to as "transgenic," "recombinant," or more currently, "genetically modified." The US has led the world in developing this technology and is the largest producer of genetically modified foods. The general population in Europe has long been opposed to genetically modified foods and European scientists have done a lot of research to probe for dangers and weaknesses in genetically modified crops.

The end result has been a lot of hype and misinformation, some good science, and the US steadily producing more and more GM crops and Europe banning GM crop importation.

What I want you to do is become familiar with the issue, discern what is good information and what is misleading information.

 

Go to http://www.sciam.com/article.cfm?articleID=0009632E-2481-1C75-9B81809EC588EF21

Read the article. It is fairly well balanced and has a "case for" and "case against" at the end. This will give you a good overview of the whole controversy.

Go to http://www.agbios.com/_Synopsis.asp
This is a very comprehensive list of GM plants currently available.
First section = crops and the traits that have been added to the plant
Second section = traits and the gene that causes that trait
Third section = what country has approved what crop for certain uses
Notice what countries are heavily involved in GM foods. Notice what the E.U. has approved.
Use the "Find" command Hit "ctrl F" and enter "European Union" into the box. Click "find next" and repeat. Notice the dates of approval for GM crops in the E.U.
What was the last year a GM crop was approved in the E.U.?

Go to /TransgenicCrops/teachers.html

on the links to the left; click "The history of plant breeding" Read
on the links to the left; click "What are transgenic plants" Read
on the links to the left; click "How to make transgenic plants"
This is a bit technical, but has several key points you need to know about.

Skim the "Introduction to DNA" section if you are a bit rusty on DNA/RNA/protein synthesis.
Read "Locating genes for plant traits"
Read "Designing genes for insertion"
Pay particular attention to the CaMV promoter and the selectable marker as these are both heavily involved in the controversy about GM foods.
Skim the remaining sections. They describe the mechanics of getting the gene into the plants. The relevant point here is the need for the selectable marker gene in the process.

on the links to the left; try the animation demo. If it doesn't work, that means we don't have the latest Shockwave plug-in loaded.
on the links to the left; click "Evaluation and Regulation" Skim this. Notice the number of different agencies involved.
on the links to the left; click "Future Transgenic Products" Skim this. Which product do you think is the most interesting?
click "Risks and Concerns" READ THIS CAREFULLY

Think a little bit and answer these questions:

What is the best evidence that the CaMV promoter is safe to eat?

 

What can be substituted for antibiotic resistance genes as a selectable marker?

 

Why would it be beneficial to biotechnology to save biodiversity?

 

What would be the negative effects of other plants developing herbicide resistance?

 

What would be the negative effects of insects developing Bt toxin resistance?

 

Would either of the two resistances have a negative effect on native populations of plants?

 

Now go to http://www.connectotel.com/gmfood/
This is the other side of the coin, people vehemently opposed to GM foods.

click on "Myths spread by the pro-GM, anti-organic movement" (at the very top) Read each section and answer the questions. Remember to think for yourself, not search the article for the answer.

E.coli:
Think ... what is the best evidence that the E. coli problem is not related to the GM issue at all?

 

Fungal toxin/Aflatoxin/Mycotoxin
Contrary to the wording of the article, this is not a 'myth' and Gary Munkvold is not necessarily pro-GM, he is just a scientist researching Bt corn because he is in Iowa where they grow tons and tons of it. They found that Bt toxin killed the fungus that makes aflatoxin. Besides the hype, what is the valid concern about this discovery?

 

Feed the world
What would need to be done to feed the world without modified crops?

 

Making allergenic food non-allergenic and Adding pharmaceutical properties to crops
Both the "allergenic vs. non-allergenic" and the "pharming" articles have the same argument.
What is the argument against using modified crops for these purposes?

 

Making food more nutritious
I couldn't find a valid argument in here anywhere. Eating a variety of foods may not be possible in many third world countries, they can put the beta carotene gene in any variety of rice you want, and there is no evidence that adding an extra nutrient imbalances other nutrients.

Hit the "Back" button on your browser and go to: What's wrong with Genetic Modification?

Read: 1 September 2000 - GM crops threaten skylarks (Guardian UK)
Why is getting rid of weeds good? Why is it bad? Propose a solution that works for both sides.

 

Skim: 29 March 2000 - Farmers using more chemicals, analysis shows (LA Times)
Is this article about GM foods? What is one of the reasons for using GM crops that relates to this article?

 

Skim: 21 September 1999 - Pesticide safety limit raised 200 times 'to suit GM industry' (Daily Mail UK) Is Roundup a pesticide (kills bugs) or a herbicide (kills plants)?
What is the new limit according to this article?

The LDLO (lowest published lethal dose) for glyphosate (the active ingredient in Roundup) is 2143 mg/kg (I got this from http://physchem.ox.ac.uk/MSDS/PH/N-(phosphonomethyl)glycine.html)
How many grams would a 90 kg man have to consume to be killed by Roundup?

If a crop of soybeans had 20 parts glyphosate per million parts soybeans, how mny grams of soybeans would you have to eat to get the LDLO dose you figured in the last question?

Convert the grams of soybeans into pounds. (454 g = 1 lb)

Skim: 25 September 2002 - Studies show Roundup herbicide to be hormone disruptor (CropChoice News) If you were to check the source of this info (EHP Vol 108) you would find the dosage that altered hormone production was .025 mg/ml glyphosate. Convert this to parts per million (ppm). Is this a realistic amount of Roundup that a person would be exposed to?

Notice the next to the last paragraph. Which method of weed control uses the least herbicide: conventional, Roundup Ready program, or Integrated Weed Management?

Either look up or ask your teacher what is "Integrated Weed Management"?

Read: 20 February 2001 - Weed develops Roundup resistance (Indianapolis Star)
Did the genes from the crops move to the weeds?
Would the weeds have developed the resistance if there were no GM crop being grown?

 

Read: 27 January 1999 - Superbugs possible from genetically modified food (BBC News UK)
(Remember the selectable markers from before?) What is the worry about using antibiotic resistance genes as markers? Did the genes transfer from the food crops to the bacteria or from bacteria to bacteria? Has anyone seen a transfer from plant to bacteria?

 

Read 28 May 2000 - GM genes 'can spread to people and animals' (Independent UK)
Where specifically was the gene transfer, from the crop to the bee or from the crop to the bacteria in the bee gut? Is the title true, the genes can spread to people and animals?

 

Now that we can sequence DNA rapidly and do whole genomes, can we check to see if any genes have transferred from plants or bacteria to people or animals?

 

Some people have a religious objection to genetically modifying foods.
Check out http://www.bio-integrity.org/RelReject.html
Are any of the references to this article from a religious source?
Find a reference to GM foods from any religion. This may or may not be on the internet.
Give the religion, the source, and the position on GM foods. This should be specific to genetic modifications of foods (plants and animals), not genetic modification of humans!!

 

 

 

Use the rest of the page to write a reflection of what you learned in this assignment.
Be sure to cover each of the following points:
>What was your position before this assignment?
>What is your position now?
>Are there real risks?
>Do they outweigh the benefits?
>What more information do you need to know about this subject?