I am an agricultural economist writing a book chapter on GMOs. I tried to explain how genetic modification takes place with the statement, "A GMO is an organism where the genes from another organism (usually a bacteria) are deliberately inserted into the organism in hopes that it will exhibit certain desirable traits, like creating its own pesticide or being resistance to a certain herbicide."

When I asked a scientist to review this statement he replied, "This is incorrect. A GM organism is one whose development involved the in vitro manipulation of DNA. This is not a petty little point. RNA can be used, no new genes may be present, and we can now make mutants that have specifically mutated genes in them but no new added DNA. Science has moved on so far that most legal definitions of GM are no longer adequate."

I'm hoping you can help me understand his statement. How can a new gene enter a DNA sequence (through human manipulation) if it was not taking from some other organism's DNA sequence?

Expert response from Dr. L. Curtis Hannah

Professor, University of Florida

Wednesday, 09/10/2013 13:21

Thank you for your important question. The definition of a “GMO” or a transgenic organism refers to an organism containing a gene inserted by man. This is quite evident when one reviews the criteria for release of these organisms as defined by the Joint Food Standards Program of the Food and Agriculture Organization of the United Nations and the World Health Organization, as well as Codex Alimentarius Commission (reviewed in Steiner, H-Y, Halpin C., Jez J., Kough J., Parrott W and , Hannah, LC. 2013 Evaluating the Potential for Adverse Interactions within Genetically Engineered Breeding Stacks. Plant Physiol, 161: 1587-1594.)

The gene need not be from another organism or from a bacterium. For example, our lab modifies corn genes and puts them back into corn and this is still considered genetically modified. Part of the “approval” process involves a determination of the position of the new insertion and some assurance that this new insertion site is not in a gene important for the plant or for food safety. Also, we use sequences from a bacterium for the insertion process that do not normally occur in maize (although they are now found in other approved maize transgenic events).

The point that the distinction between transgenic and non-transgenic is murky (and in some cases nonsensical) is quite valid. For example, the bacterial sequences that insert the genes into plants to make transgenics mentioned above do this naturally in nature and yet this is not regulated when it occurs in nature. Also, there exists much genetic variation in nature. Two corn inbred chosen at random are more distantly related than man is to the chimpanzee, yet we are not really concerned about how this “natural” variation affects food safety.

I look forward to the day when this issue of classification and approval is based more on science than it is on politics and fear mongering.