Dr. L. Curtis Hannah

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Dr. L. Curtis Hannah

Professor, University of Florida

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.

From this Expert

Posted on: January 31, 2018
Response from Dr. L. Curtis Hannah, Professor, University of Florida • May 18, 2018
Thank you for your question. There are various aspects of your question. I assume your question refers to the use of Agrobacterium rhizogenes by scientists to intentionally transfer genes from the bacterium to plants. Infection and DNA transfer from this bacterium occurs in nature all the time to cause disease. Such transformed plants are not classified as GMOs since transfer occurred naturally. If this is done by scientists then it would be classified as a GMO. Rules and... Read More
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Posted on: March 5, 2016
Response from Dr. L. Curtis Hannah, Professor, University of Florida • April 19, 2016
Thanks for such an interesting question. I like this because it allows me to discuss the vast area of gene movement and gene variability that occurs in living organisms. Initially, one can go back to “the beginning” of higher life forms such as the plants we grow, the animals in our lives and yes even “us” and note that some of the organelles we have in our cells originally came from bacteria. All higher life forms have mitochondria and plants have chloroplasts as well... Read More
Posted on: December 11, 2015
Response from Dr. L. Curtis Hannah, Professor, University of Florida • April 19, 2016
Thanks for a great question!! Your question addresses much of the confusion in the popular press. To a geneticist, genetic modification means exactly what the words say: there is modification in the genetic material. This heritable form of variation of course is caused by mutation. Mutation can be natural or induced. Classic agents that induce mutation are some chemicals and some forms of radiation. For years, plant breeders have used induced mutation breeding to create favorable traits in... Read More
Posted on: November 1, 2015
Response from Dr. L. Curtis Hannah, Professor, University of Florida • December 11, 2015
Thank you for your question. Roundup Ready refers to plants genetically engineered to be resistant to the herbicide Roundup. The active ingredient in this herbicide is a chemical called glyphosate. This chemical blocks the production of an essential component needed for plant life and consequently the plant dies after treatment with this herbicide.     More specifically glyphosate inhibits an enzyme called 5-enolpyruvylshikimate 3-phosphate synthase, sometimes abbreviated... Read More
Posted on: July 30, 2015
Response from Dr. L. Curtis Hannah, Professor, University of Florida • August 21, 2015
Thanks for the question. I had to do some digging on this one. In terms of which person-directed mutagenesis method is more common among commercial varieties, Ahloowalia et al (Euphytica 135: 187-204, 2004) state that radiation is the most frequently employed method used by plant scientists. This work is somewhat dated (2004), but since people have been using X-rays since 1927 to create gene variants in plants, I would be surprised if the story has changed in the last 12 years. These... Read More
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