Groose explains all food is genetically modified, looks at technology available
Laramie – In the wake of the University of Wyoming’s 2014 Consumer Issues Conference, titled, “Food: Perceptions, Practices and Policies,” University of Wyoming Associate Professor Robin Groose noted that only one side of the conversation related to genetically modified foods, or GMOs, was portrayed.
“Pretty much everything we eat has been genetically modified in one way or another,” Groose said. “All different kinds of genetic modification are used to improve plants.”
Understanding modifications
During his presentation, Groose looked at a variety of methods used to genetically modify plant species, noting that there is discussion over what is “genetic modification.”
“Genetically modified refers to a range of methods used to alter the genetic composition of a plant or animal, including traditional hybridization and breeding,” Groose explained. “Genetic engineering is one type of genetic modification that involves making an intentional targeted change in a plant or animal gene sequence to affect a specific result.”
Why modify?
He continued that the goal of genetic modification is to improve plants and modify how they interact with their environment.
“I think our goal in sustainable agriculture is in terms of the environment and profitability for growers,” said Groose.
Further, he noted that genetic modification of plants in agriculture has enabled increased production and yields, citing improved wheat yields in developing countries.
“Populations are going up,” he said. “At the same time, it is taking fewer farmers to feed more people. Yes – many people go to bed hungry, but on the whole worldwide, people are better fed than ever before.”
Longterm modifications
“The ideas of evolution had been around a long time before Darwin, but he identified natural selection,” Groose commented.
As an example, Groose used maize, which started out as a species called teosinte, which has a hard outer shell surrounding each kernel. Mutations over time resulted in maize that was soft on the outside and easier to eat. It was hunter-gatherer populations who selected for the favorable plants.
“Darwin referred to the selection that agriculturalists were dong as artificial selection,” he said. “Darwin wasn’t implying the stuff we do is fake, he meant ‘artificial’ in terms of producing an artifact.”
Cultivated improvements
In looking at cultivated plants, Groose also noted that artificial selection takes place, as well as traditional plant breeding techniques and modern genetic modification.
“Breeding and biotechnology really compliment one another,” he said. “On the breeding side, we have hybridization and selection, and that is the core of modern plant breeding.”
Biotechnology can be broken into three areas – cell culture, micro-propagation and in vitro technologies.
“The goals of all of these modification techniques are the same, as far as I’m concerned,” Groose said. “We are looking for genetically superior plants.”
Modern tools
Many tools exist for modern plant breeders to utilize, many of which fall under the spectrum of conventional plant breeding technology.
“We manipulate chromosomes, bits of chromosomes and whole genomes,” Groose explained. “There are 25,000 loci on a plant genome. Genetic engineering generally deals with one or very few genes at a time, whereas plant breeders mess with the whole genome.”
“In my opinion, I can imagine unwanted, unintended consequences from traditional plant breeding being more likely than from genetic engineering,” he added.
Emasculation
Groose highlighted eight examples of genetic modification techniques to demonstrate both plant breeding and biotechnology – emasculation,
“Emasculation is a technique to hybridize normally self-pollinated plants to create new inbred pure lines,” he explained. “We remove the anthers from a female plant and, using a camel’s hair brush, we transfer the pollen to the stigma.”
The process is achieved by removing the sepals and petals of the flower before it opens.
“Emasculation doesn’t occur in nature,” Groose continued. “We have made lots of crosses between pea lines and advanced using this technique.”
Backcrossing
Backcrossing is another traditional technique that involves crossing two plants and growing a plant from the resulting seeds. The technique ultimately incorporates the desirable gene from the recurrent parent to the offspring.
“Then, we backcross it over and over again to our recurrent parent, selecting for resistance throughout,” he explained. “Along the way, we dilute the genes that come from the donor to approach the genotype of the recurrent parent.”
Groose added, however, “We aren’t just transferring the desired gene. We are also transferring anything that is tightly linked to our resistant gene.”
F1 hybrid cultivars are used in American agriculture to provide hybrid vigor in species.
“It is possible to find pairs of inbred lines that, when combined, exhibit hybrid vigor,” he said, noting that varieties of corn in the Midwest yielding 300 bushels and more per acre are hybrid varieties.
Allopolyploids
Next allopolyploidization is a genetic evolution mechanism that often occurs naturally.
Allopolyploid plants have multiple sets of chromosomes. For example, wheat used for bread has six chromosomes.
However, Groose mentioned, “Not long ago in Northern Europe and Scandinavia, people were interested in growing small grains with more winter hardiness than bread wheat exhibited.”
The wheat was crossbred with rye, creating an interspecific hybrid species with four sets of chromosomes. While the plants are sterile, the plants yielded are larger and more robust.
“It is from the seed that we get a new allopolyploid,” Groose says. “In this case, we got triticale.”
“We are messing with a lot of genes in classical plant breeding,” he continues. “We are dealing with whole sets of chromosomes, each with 25,000 genes.”
Plant Examples
UW Associate Professor Robin Groose noted that many cultivars are genetically improved, including a number of Wyoming’s top crops.
“Breeders break plants into four fundamental populations,” he explained. “We have inbred pure lines, open pollinated populations, hybrids and clones.”
Groose identified many wheat, barley and dry bean lines as inbred pure lines. Open pollinated populations include alfalfa. Sugarbeets and corn are hybrid, and potatoes are clones.
Specifically in Wyoming, 100 percent of the sugarbeet crop is a genetically modified variety, and most of the corn in the state is also a genetically modified variety. He also cited that some alfalfa is modified to be Roundup-resistant.
Look for more information from Groose on more technologically advanced methods of genetically modifying plants in an upcoming edition of the Roundup.
Saige Albert is managing editor of the Wyoming Livestock Roundup and can be reached at saige@wylr.net.
