Over the past 20 years I have been asked by friends, family, community groups and students about my opinion on genetically modified food. It has been frustrating for me to try and give a satisfying answer to these questions, as they are often focused on one little part of this large field of science and agriculture.
In 1988, I joined a group of researchers from UC-San Diego, San Diego State University, Scripps Clinic and the Salk Institute to discuss the problems facing agriculture. Our focus was to decrease the toxicity and quantities of chemicals being used while increasing yields and nutrition of crops. Some of the biggest problems farmers were facing included disease, drought and weeds.
We talked about the common use of wild type versions of cultivated plants for plant breeding. These plants had been used for hundreds of years as a source of genetic material to cross with cultivated varieties in an effort to regain desired traits like disease resistance. However, there were two problems:
* The breeding process to get the desired traits from the wild type plants into the cultivated variety and then to backcross out all the unintended traits that came with it took, on average, seven to 10 years.
* The inability to cross many cultivated plants with their wild type variety, as many had diverged so much genetically that the crosses were sterile.
We thought about how much time could be saved, unintended effects of plant breeding avoided and use of chemicals decreased if we could just move in a selected gene or set of genes for a given trait.
This idea of giving a plant a naturally occurring gene to give it resistance to a pathogen or another desired trait is analogous to giving humans bone marrow transplants when they are missing or have damaged genes.
One of the most amazing things that we have learned from genetics is that evolution started with single-celled organisms with a few sets of genes that governed how they lived and reproduced. Over billions of years, as these organisms adapted to different environments and became multicellular organisms, they developed new or slightly different versions of the same genes and many genes remained the same throughout all life forms. 99.9 percent of all proteins begin with the exact same amino acid code that we call the start codon. There are also only 20 amino acids that make up all proteins.
This idea of a gene being taken from one organism and put into another as being foreign or a contaminate makes no sense. DNA is the essence of life and is as organic as it gets.
Viruses carry genes from one organism to another regularly and so do many bacteria. Natural selection based on the environment determines what will survive. It's important to remember that we eat the DNA of other organisms every day in the plants and animals we consume as well as many unintended bacteria, viral, fungal and sometimes insects that have found their way into our food. If there was a problem with eating the genes of other types of organisms, life could not exist as we know it.
When talking about genetically engineered crops, we hear mostly about Roundup Ready and Bt crops. It's important to note that Roundup is used in traditional as well as GE farming, and Bt chemicals are used throughout all types of agriculture, including organic. The gene used in GE plants that gives plants resistance to Roundup came from a bacterium called agrobacterium, and the Bt toxin gene came from the common soil bacterium Bacillus thuringiensis.
The GE papaya developed by the University of Hawaii utilized a gene for the coat protein of the papaya ringspot virus. This gene acts like a vaccine to silence the reproduction of invading ringspot viruses. People who eat non-GMO papayas have likely eaten ones that were infected with this virus and have therefore eaten the coat protein gene along with all the genes of the virus.
The facts are: A moratorium on GMOs will increase chemical use and lower yields, and GMO crops are rigorously tested and regulated for safety.
For more information, see www.isaaa.org/resources/publications/briefs/46/topfacts/default.asp.
* Sally Irwin, Ph.D., is a plant geneticist. She lives on Maui and has worked for the University of Hawaii for 18-plus years.