Why do scientists genetically modify food

Most of the foods we eat today were created through traditional breeding methods. But changing plants and animals through traditional breeding can take a long time, and it is difficult to make very specific changes. After scientists developed genetic engineering in the s, they were able to make similar changes in a more specific way and in a shorter amount of time.

PDF KB. Circa BCE Humans use traditional modification methods like selective breeding and cross-breeding to breed plants and animals with more desirable traits. This policy describes how the U. Not all are still available for sale. Genetic engineering is a process that involves:. Fact Sheet. The following example gives a general idea of the steps it takes to create a GMO plant. To produce a GMO plant, scientists first identify what trait they want that plant to have, such as resistance to drought, herbicides, or insects.

One of the problems with selective breeding is that it can also result in traits that are not desired. Genetic engineering allows scientists to select one specific gene to implant. This avoids introducing other genes with undesirable traits. Genetic engineering also helps speed up the process of creating new foods with desired traits. These concerns have thus far been unfounded. None of the GE foods used today have caused any of these problems.

They assess the safety of GE foods to humans, animals, plants, and the environment. Cotton, corn, and soybeans are the main GE crops grown in the United States. Most of these are used to make ingredients for other foods, such as:. The World Health Organization, the National Academy of Science, and several other major science organizations across the globe have reviewed research on GE foods and have found no evidence that they are harmful. There are no reports of illness, injury, or environmental harm due to GE foods.

Genetically engineered foods are just as safe as conventional foods. The US Department of Agriculture has recently started requiring food manufacturers to disclose information about bioengineered foods and their ingredients. Traditional breeders cross related organisms whose genetic makeups are similar.

In so doing, they transfer tens of thousands of genes. By contrast, today's genetic engineers can transfer just a few genes at a time between species that are distantly related or not related at all. Genetic engineers can pull a desired gene from virtually any living organism and insert it into virtually any other organism. They can put a rat gene into lettuce to make a plant that produces vitamin C or splice genes from the cecropia moth into apple plants, offering protection from fire blight, a bacterial disease that damages apples and pears.

The purpose is the same: to insert a gene or genes from a donor organism carrying a desired trait into an organism that does not have the trait. The engineered organisms scientists produce by transferring genes between species are called transgenic. Several dozen transgenic food crops are currently on the market, among them varieties of corn, squash, canola, soybeans, and cotton, from which cottonseed oil is produced.

Most of these crops are engineered to help farmers deal with age-old agriculture problems: weeds, insects, and disease. Farmers spray herbicides to kill weeds. Biotech crops can carry special "tolerance" genes that help them withstand the spraying of chemicals that kill nearly every other kind of plant. Some biotech varieties make their own insecticide, thanks to a gene borrowed from a common soil bacterium, Bacillus thuringiensis , or Bt for short. Bt genes code for toxins considered to be harmless to humans but lethal to certain insects, including the European corn borer, an insect that tunnels into cornstalks and ears, making it a bane of corn farmers.

So effective is Bt that organic farmers have used it as a natural insecticide for decades, albeit sparingly. Corn borer caterpillars bite into the leaves, stems, or kernels of a Bt corn plant, the toxin attacks their digestive tracts, and they die within a few days. Other food plants—squash and papaya, for instance—have been genetically engineered to resist diseases. Lately scientists have been experimenting with potatoes, modifying them with genes of bees and moths to protect the crops from potato blight fungus, and grapevines with silkworm genes to make the vines resistant to Pierce's disease, spread by insects.

With the new tools of genetic engineering, scientists have also created transgenic animals. Atlantic salmon grow more slowly during the winter, but engineered salmon, "souped-up" with modified growth-hormone genes from other fish, reach market size in about half the normal time.

Scientists are also using biotechnology to insert genes into cows and sheep so that the animals will produce pharmaceuticals in their milk. None of these transgenic animals have yet entered the market. With genetically engineered foods we minimize risks by doing rigorous testing. According to Eric Sachs, a spokesperson for Monsanto, a leading developer of biotech products: "Transgenic products go through more testing than any of the other foods we eat.

We screen for potential toxins and allergens. We monitor the levels of nutrients, proteins, and other components to see that the transgenic plants are substantially equivalent to traditional plants. Three federal agencies regulate genetically engineered crops and foods—the U.

The FDA reviews data on allergens, toxicity, and nutrient levels voluntarily submitted by companies. If that information shows that the new foods are not substantially equivalent to conventional ones, the foods must undergo further testing. Last year the agency proposed tightening its scrutiny of engineered foods, making the safety assessments mandatory rather than voluntary. In the mids a biotech company launched a project to insert a gene from the Brazil nut into a soybean.

The Brazil nut gene selected makes a protein rich in one essential amino acid. The aim was to create a more nutritious soybean for use in animal feed. Because the Brazil nut is known to contain an allergen, the company also tested the product for human reaction, with the thought that the transgenic soybean might accidentally enter the human food supply. When tests showed that humans would react to the modified soybeans, the project was abandoned. For some people this was good evidence that the system of testing genetically engineered foods works.

But for some scientists and consumer groups, it raised the specter of allergens or other hazards that might slip through the safety net. Scientists know that some proteins, such as the one in the Brazil nut, can cause allergic reactions in humans, and they know how to test for these allergenic proteins. But the possibility exists that a novel protein with allergenic properties might turn up in an engineered food—just as it might in a new food produced by conventional means—and go undetected.

Furthermore, critics say, the technique of moving genes across dramatically different species increases the likelihood of something going awry—either in the function of the inserted gene or in the function of the host DNA—raising the possibility of unanticipated health effects.

An allergy scare in centered around StarLink, a variety of genetically engineered corn approved by the U. When StarLink found its way into taco shells, corn chips, and other foods, massive and costly recalls were launched to try to remove the corn from the food supply. No cases of allergic response have been pinned to StarLink. In fact, according to Steve L. Taylor, chair of the Department of Food Science and Technology at the University of Nebraska, "None of the current biotech products have been implicated in allergic reactions or any other healthcare problem in people.

Only rigorous testing can minimize those risks. Often overlooked in the debate about the health effects of these foods is one possible health benefit: Under some conditions corn genetically engineered for insect resistance may enhance safety for human and animal consumption.

Corn damaged by insects often contains high levels of fumonisins, toxins made by fungi that are carried on the backs of insects and that grow in the wounds of the damaged corn. Lab tests have linked fumonisins with cancer in animals, and they may be potentially cancer-causing to humans. Among people who consume a lot of corn—in certain parts of South Africa, China, and Italy, for instance—there are high rates of esophageal cancer, which scientists associate with fumonisins.

Studies show that most Bt corn has lower levels of fumonisins than conventional corn damaged by insects. Should genetically engineered foods be labeled? Surveys suggest that most Americans would say yes although they wouldn't want to pay more for the labeling.

Professor Marion Nestle, chair of the Department of Nutrition and Food Studies at New York University, favors labeling because she believes consumers want to know and have the right to choose. However, no engineered foods currently carry labels in the U. Industry representatives argue that labeling engineered foods that are not substantially different would arouse unwarranted suspicion.

Most scientists agree: The main safety issues of genetically engineered crops involve not people but the environment. Snow is known for her research on "gene flow," the movement of genes via pollen and seeds from one population of plants to another, and she and some other environmental scientists worry that genetically engineered crops are being developed too quickly and released on millions of acres of farmland before they've been adequately tested for their possible long-term ecological impact.

Advocates of genetically engineered crops argue that the plants offer an environmentally friendly alternative to pesticides, which tend to pollute surface and groundwater and harm wildlife.