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Dr. L. Curtis Hannah

Professor, University of Florida

Expert Bio

Dr. L. Curtis Hannah is a Professor of Plant Molecular and Cellular Biology teaching Advanced Genetics at the University of Florida. His areas of research include plant molecular biology, plant genetics, starch biosynthesis and transposable elements. Dr. Hannah’s work focuses on engineering heat labile enzymes that play important roles in maize yield. Some variants give rise to as much as a 68% increase in maize yield in hot environments. He earned his Ph.D. in genetics at the University of Wisconsin after completing bachelor’s and master’s degrees in biochemistry and genetics at Purdue University. He remains active in the family farming operations in Indiana.

Studies, Articles and Answers

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Q: What are the breeding obstacles to releasing GMO traits in hybrid seed? What are the performance liability issues related to same, and what are the regulatory issues related to such a release into the environment?

Answered By Dr. L. Curtis Hannah - Sep 04, 2013

A: First, thank you very much for your series of questions.  In terms of regulatory issues for releasing transgenic cultivars that are hybrid (such as corn or maize), versus, I assume, ones that are not (such as soybeans), there are no formal differences in the regulatory process. Questions concerning the nature of the gene, its function, its insertion site in the host genome, effect on plant growth and composition, allergenic properties of the added protein, etc., must be satisfied before the transgene can be “deregulated” and used commercially. Your question may be getting at the fac [...]

GMO Basics GMOs & Farmers How GMOs Are Made


Q: 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

Answered By Dr. L. Curtis Hannah - Oct 09, 2013

A: 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 Stack [...]

Health & Safety How GMOs Are Made


Q: Some of the answers I've read on your website make it seem like the science of genetic modification is completely precise: 1) that a foreign gene is inserted exactly where it needs to go without any disruption of the genes on either side of it and 2) that

Answered By Dr. L. Curtis Hannah - Dec 09, 2013

A: I love your questions because it allows me to address some of the confusion out there concerning GMOs. The ability to precisely insert a gene at a particular site in the genome is an area of active research. The day likely will come when all new gene inserts are done at precise locations.  However to the best of my knowledge all commercially used gene inserts in today’s market arose from methodologies that did not use precise insertion techniques.  However, following insertion the location of the inserts in commerce was precisely determined by DNA sequencing. Knowing this infor [...]

How GMOs Are Made


Q: How can Monsanto assure that artificial GMO genes do not propagate into natural ecosystems or non-GMO crops?

Answered By Dr. L. Curtis Hannah - Mar 07, 2014

A: Thank you for your question. In order for Monsanto to be in a position to make such assurances, it would have to have total control of plant agriculture, from planting to consumption. This is not the way modern agriculture and the food chain function. And I have not heard of any suggestion that Monsanto (or any other seed company that sells GMO crops) should control these activities. It should be mentioned that seed producers have the right to protect their invention from subsequent unlicensed propagation, through the Plant Variety Protection Act or conventional utility patents. The [...]

Health & Safety How GMOs Are Made