Tomorrows Table: What does GMO really mean?

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Tomorrows Table: What does GMO really mean?


For years, journalists, television producers and newspaper reporters that write about genetically engineered crops, have used the term “GMO” (genetically modified organism) to describe these new crop varieties. The marketing industry has taken to writing “GMO-free” on their products, as a way to increase sales to consumers fearful of the genetic engineering process.

The problem is that the term GMO is misused and misunderstood.

Take, for example, a recent story on Voice of America about a newly developed rice variety that is tolerant of flooding. The producer made a valiant effort to explain the genetic basis of this new variety:

“The new strain is genetically improved, but not genetically modified, so is not subject to tight controls on genetically modified foods.”

Does anyone know what is he talking about? I do, so please let me explain.

Breeders have a 8000 year history of genetic modification (also called genetic improvement or conventional breeding)- that is, they have modified the genome of crop species in a number of ways. Such conventional breeding methods include hybridization (transfer of pollen from one plant variety to another to generate new seed with genes from both parents), mutagenesis (in which chemicals or irradiation are used to induce random mutations in DNA) and embryo rescue (where plant or animal embryos produced from interspecies gene transfer are placed in a tissue culture environment to complete development). Today, everything we eat has been genetically modified in some way.

Genetic engineering, in contrast, uses a direct method to introduce new genes into a crop. Because the transfer is not limited by the relatedness of the parental varieties, any gene, even a gene from another species can be introduced into a crop plant. A committee established by the National Academy of Sciences was asked to look carefully at the GE process. Their report concluded that the process of genetic engineering is not inherently hazardous. However, as with every other technology used for genetic modification, GE carries the potential for introducing unintended compositional changes. It depends on what gene is introduced or modified. For example, a new celery variety developed through conventional breeding that carried improved resistance to pests caused some farm workers to develop a rash on their hands when harvesting. In contrast, after 1 billion acres of GE crops grown over 10 years, there has not been a single instance of harm to human health or the environment.

The method that we used to develop flood tolerant rice is called precision breeding, which is a sort of hybrid between genetic engineering and conventional genetic modification. Precision breeding (also called marker assisted selection) uses DNA technology to detect the inheritance of a desired gene to a seedling resulting from a genetic cross between two parent varieties. The result is the precise introduction of one to several novel genes from closely related species. For example, our flood tolerant rice was developed from a cross of a low-yielding rice variety that carried 
a rare gene for tolerance with modern, locally adapted modern varieties. The resulting seedlings were screened using precision breeding to develop new varieties with the taste and yield favored by consumers with the flood tolerant trait. This year the rice was grown by 2 million farmers in Bangladesh and India, where 4 million tons of rice are lost each year to flooding, enough to feed 30 million people.

Many anti-GE activists reject GE but do accept precision breeding (even though both processes can introduce novel genes that have not previously been tested in modern varieties). Thus, varieties developed through precision breeding are subject only to standard seed certification and not to the strict regulatory approval process required for GE crops.

We need to look at the broader goals of sustainability and food security before ruling out a particular process of crop modification. Each new variety needs to be evaluated on a case-by case basis.

To restart the dialog, lets use the term “GE crops” rather than “GMO” so the consumer will have a better idea of what the debate is all about.

First published on google news.

Follow Pamela Ronald:

Pamela Ronald is Professor of Plant Pathology at the University of California, Davis, where she studies the role that genes play in a plant’s response to its environment. Her research focuses on the genetics of rice. With her husband, she co-wrote Tomorrow's Table: Organic Farming, Genetics and the Future of Food. She writes a blog of the same name.