The history of genetically modified organisms – GMOs – in agriculture actually began before recorded history. Prehistoric farmers have been selecting the most productive plants and seeds from their domesticated crops for up to 10,000 years.
What changed in the last quarter of the 20th century was that scientists began selecting productive traits at the individual gene level and controlling the placement of genes in new crops.
The scientific study of genes began in the 1860s when Austrian monk Gregor Mendel systematically crossed varieties of garden peas. He introduced the concept of a “gene” as a unit of heredity. In 1868, German chemist Friedrich Meischer discovered the substance we now call DNA, Deoxyribose Nucleic Acid. But scientists thought it was too simple chemically to carry the vast amount of genetic information required to produce the enormous diversity of nature. Proteins, they thought, were the basis of genetics.
In 1944, Oswald Avery tentatively identified DNA as the true carrier of molecular information, and his findings were confirmed in 1952. Less than a year later, in 1953, James Watson and Francis Crick described DNA’s molecular shape as a double helix. That opened the door to genetic engineering.
It’s one thing to describe how different sequences of only four chemical “base pairs” can manufacture proteins that then create genetic differences. It’s quite another thing to precisely “manufacture” new sequences that produce a desirable effect in a living organism. That is the science that produced genetically modified organisms, or GMOs.
The art of gene splicing dates from 1972. In that year, Stanley Cohen and Herbert Boyer developed techniques that made it possible to chemically cut and splice strands of DNA at specific places in the sequence. Boyer used an enzyme to cut the code for a specific protein and attach it to other DNA. Cohen added a way to introduce these DNA sequences into bacteria and yeast cells. Together the two scientists turned these microbes into hormone factories. In 1976, they founded the new company Genentech and introduced human genes that produce insulin into strains of bacteria. Those bacteria started manufacturing insulin. Next, they manufactured human growth hormone. HGH was used to enable dwarf children to grow to normal size. Before genetic modification techniques, the only source for the drug had been human cadavers.
In 2009, Genentech was bought by the Swiss drug maker Roche for $47 billion.
Gene-splicing technology entered the food industry in 1990 when the FDA approved the safety of a new strain of GMO rennet. Rennet is used to curdle milk to form curds and whey, the raw material of cheese and other dairy products. The pharmaceutical giant Pfizer had isolated the gene for making rennet from the stomach of a calf – the previous source of the enzyme – and inserted it into bacteria.
By 1995, fully 67 percent of the cheese produced in the U.S. was being made with rennet from genetically modified organisms.
In 1994, Monsanto introduced a form of bovine growth hormone (BGH) that was manufactured by genetically modified bacteria. Farmers could inject the hormone directly into dairy cattle to increase their milk production. Critics were concerned that the hormones could get into the milk supply and possibly harm the cows. However, for the most part, the public and the farmers have accepted BGH.
Bt Crops. The next step in genetically modifying organisms for food was to ramp up from bacteria – with thin cell walls – to plants that have thick, tough cell walls. In 1976, agricultural researchers at the University of Washington discovered that a small, circular DNA molecule called a plasmid could insert itself into the nucleus of a plant cell and cause tumors. They had discovered what amounted to a natural form of gene splicing.
Enzymes were also developed to make the walls of plant cells porous. By 1983, scientists at two universities and the seed giant Monsanto had figured out how to take out harmful genes from plasmids, insert the desired gene and get the plasmid into the plant cell where it would introduce the gene into the nucleus of the plant itself.
These techniques opened the floodgates for genetic engineering, and lead to the development of Bt, Roundup Ready and other genetically modified crops that will be covered in the next story.
Genetically modified crops have taken over in most of the major agricultural states. According to the USDA, by 2008, 92 percent of the soybeans planted in the U.S. were GMO varieties. Nebraska and South Dakota were the two highest percentage states at 97 percent each.
Genetically modified corn was planted in 80 percent of the fields in the U.S. by 2008. Again, sophisticated farmers in the Midwest led the way. Nebraska farmers planted 86 percent GMO corn while South Dakota topped the list of states at 95 percent GMO corn.
But not everyone is thrilled with GMOs. Notably, several European Union countries have banned the import of GMO crops.
Troy Otte (left) is one of those farmers who is not concerned with the potential for harmful affects from GMOs. He believes that the techniques could vastly improve corn yields from the current 150 bushel per acre average. “We could see a 300 bushel average,” he says. “As far-fetched as that may sound they’re saying the biotech era will be the new Industrial Age.”
Professor Don Lee (right) says that what the genetic engineers are doing is simply a different form of traditional plant breeding. “You’re capitalizing on the same motivations that breeders have always had. They need genetic variability if they’re going to make progress on solving a problem like disease resistance.,” he says. “In genetic engineering, you can actually take a gene from any species and integrate it into the genetic information molecule that the plant already has. So, you’re adding new genetic variation.”
Despite the concerns about genetically modified organisms, it appears that the question in the future will not be whether or not GMOs will be used but how they will be managed.
Written by Bill Ganzel, the Ganzel Group. First published in 2009. A partial bibliography of sources is here.