Table of Contents | Chapter 7
John and Elsa Will Profit
|Genetic engineering can produce crops that are more resistant to disease or that taste better.|
Have you ever tried to figure out how something works, for example, a clock or a motor? One way to learn is by taking the object apart. Genetic researchers do the same thing. They cut apart the genome to figure out what the individual parts do. Researchers have found ways to slice genes out of a genome. They have learned how to make changes to a gene and how to replace one gene with another. This "cutting and pasting" is called genetic engineering, and it's a very useful way to do research.
Say, for example, that researchers want to find out what different genes do in a particular kind of flowering plant. They can take a seed from that plant and use a special technique to get inside its genome. Once inside, they can cut out a single gene. Then they can let the seed grow to see what kind of plant it makes. If the plant that develops doesn't have any petals, it means the gene they cut out is important for making flowers. If the plant ends up with too many petals, it means the gene is important for stopping petal growth. Researchers repeat this experiment many times, cutting out different genes each time. In this way, they are able to match genes to the instructions they give.
Researchers then use this information to learn about the genes of other species. For example, finding the gene that controls petal growth in one plant helps researchers find similar genes in other plants. These clues also can help researchers find genes that control growth in animals.
|Dog breeds were developed through many years of selective breeding by humans.|
Genetic engineering is important for basic research, but it also is at the heart of a whole new industry called biotechnology, or "biotech" for short. Biotechnology is the use of living things to make products. Biotechnology is not new. People have long known how to use yeast to make bread rise and how to use bacteria to ferment beer and wine or to age cheese. In today's biotechnology industry, modern biological tools are used to make products.
One such tool is genetic engineering of plants and animals. In the past, humans changed many species through selective breeding. They saved the seeds from their best plants for use as next year's crop, and they took the best animals from their herds to mate together. Through trial and error, and over many generations, this process shaped the traits of numerous species. Many of today's food crops, such as wheat and rice, were developed through thousands of years of selective breeding. So were farm animals such as cows and pigs and pets such as the many kinds of cats and dogs.
The genetic engineering that is done in biotech is far faster and more precise than selective breeding. By inserting, removing, or making changes to genes, new forms of plants and animals can be created in one generation. What is even more awesome about biotech is that it can easily overcome the barriers between species. Many new biotech products are made by transferring genes from one species into another. A transgenic plant or animal is one that contains genes from another species.
While many biotech creations are still in the experimental stage, a growing number are already on the market, both in the U.S. and in other countries. Here are some examples of what's coming out of biotech labs:
|Square tomatoes? Some farmers want to raise tomatoes that are easier to pack in boxes than round ones are.|
Research labs in nearly every country of the world have jumped into biotech. Big corporations, governments, and universities have invested in it, and hundreds of small new companies have entered the field. Billions of dollars are being spent on biotech research, and billions of dollars stand to be made from the new products.
Biotechnology is having a huge impact in many areas of our lives, from medicine to industry. Agriculture also is being affected. Farmers are having to decide how to keep up with the changes. That is the issue for Elsa and John, who are thinking about using a genetically engineered drug on their dairy cows.
The drug they are considering is an artificially produced hormone. Hormones are proteins produced by organs of the body that trigger activity in other locations. Cows produce a natural hormone called bovine growth hormone, or BGH, that causes them to make milk.
Researchers have found the gene in cows that triggers the release of BGH. They have figured out how to clone the gene in order to produce BGH artificially. "To clone" means "to make an exact copy of." Some cells are removed from a cow, and the gene for BGH is cut out of their genome. The gene is then injected into bacteria. Bacteria reproduce very quickly. As each new cell of bacteria is made, a new copy of the gene also is made. In this way, millions of copies of the gene are produced in a short time. With millions of copies of the gene, lots of BGH gets produced. The BGH is then strained out of the bacteria and sold as a drug. Giving cows this drug increases the amount of milk they produce by as much as 15 percent.
More milk from their cows could mean more money for Elsa and John. However, to make that extra money, they will have to spend more up front. There will be the cost of purchasing the hormone. Then, there will be the added costs of keeping the cows fit. This is because some studies suggest that cows treated with the hormone suffer more health problems than untreated cows. Also, there will be the cost of replacing their herd more frequently. This is because treated cows "give out" more quickly.
Elsa and John also have to decide if consumers will want their milk. Many studies say that the milk from treated cows is perfectly safe. The government also runs an inspection program for milk to make sure that it is safe. Even so, some people are concerned that the milk may contain trace amounts of the hormone. They also fear that the milk may be tainted by the extra doses of antibiotic drugs these cows need to stay healthy.
Some people are against the development of products like BGH because they say that in the long run it will hurt family farms like Elsa and John's. Large corporate farms can afford the added costs of using BGH, but smaller ones cannot and may be pushed out of business. BGH also may lead to the overproduction of milk, causing milk prices to drop. Large farms with big volume can survive on smaller profit margins, but small farms may not be able to.
Animal rights groups also have been critical of BGH because it is hard on the cows. According to them, BGH is tailor made for a "factory" style of farming in which animals are penned up, closely controlled, and pushed to overproduce. These groups say that farms can succeed without BGH through well-managed selective breeding and by more humane and healthful treatment of their livestock.
Similar concerns are raised over crops that have been engineered to resist pests and weeds. On the one hand, farmers raising these kinds of crops would probably not have to spray so much to control their fields. This could save the farmers money and be better on the environment. On the other hand, mutations of the pests and weeds could develop that would overcome the resistance of the genetically engineered crops.
Furthermore, there is the possibility that the engineered crops could cross with closely related plants. This could lead to new species of weeds that are even harder to control. Sooner or later, pests and weeds could once again be a problem. If that happens, farmers would have to use more spray. Or they would have to invest in new seed from a new generation of engineered crops.
Arguments also have been raised against genetic engineering for more productive crops and livestock. According to this argument, we don't really need to produce more food. What we need to do is overcome politics and distribution problems so that food gets to hungry people. Biotech promises to bring food closer to people who need it by creating crops and animals that can be raised in whole new climates. However, this could lead to the destruction of even more wildlife areas.
Some people argue that instead of using biotech to increase the food supply, we should change the world's eating habits. One suggestion they have is that people should eat less meat, because cattle require so much land for grazing. More meals could be produced off that land if it were used for raising crops instead.
Those who support biotech farming respond to all of these arguments by saying that we can't go back in time. The world's population is growing rapidly. It's too risky to assume that we will have enough food for everyone by persuading some people to change their diets. A better solution is to use biotech to develop more efficient ways of making food. If family farms disappear in this process, then that is the price that must be paid.
Supporters of biotech farming also respond to the concerns about the treatment of animals and destruction of wildlife areas. They say that these problems are not new, and biotech farming should not be the scapegoat. They say that problems should be addressed and solved, but that condemning biotechnology is not the answer.
The issues raised by biotech spill over into many areas beyond farming practices. One big question that biotech raises is whether it is right to alter the genes of animals. Another big question is whether it is right to make transgenic animals.
The scientists who do this kind of research say that the benefits to humans will be enormous. They also point out that animals have long been used in service to people. As an example, they point out that we raise pigs for bacon, so why not raise them to be organ donors? They argue that genetic engineering is just a new form of selective breeding, which humans have been doing for thousands of years. They also point out that the transfer of genes across species occasionally happens in nature, so it is not "unnatural" for humans to do it.
Others say that such a human-centered attitude is wrong. They say that animals are more than a collection of cells to be tinkered with at will. Rather, they are unique living beings with the right to exist for themselves. They also say that genetic engineering is potentially more harmful than selective breeding, because it can be used to change the traits of a species so quickly.
Another big question is whether we know enough to control the effects of our biotech experiments. There is a saying that in nature you can't change just one thing. Altering one trait of a species may affect it in more than one way. Creating transgenic bacteria, bugs, plants, or animals may have unintended effects. Some people say that researchers don't know enough about how genes operate to be doing this kind of work. They say that the researchers are "playing God." These people recognize that useful products are coming out of biotech. However, they worry that just one experiment gone wrong could cause a lot of harm.
Researchers respond that they have strong controls in place to make sure that their biotech experiments and products are safe. They also point out that many different government agencies regulate the industry. Finally, they say that it is easy to understand the questions about safety, but it isn't so easy to understand the answers because they involve so much science. By educating the public, biotech experts hope to win more support for their industry.
The tools of biotech, now that they have been discovered, are not going to be put aside. The question is how we will use these tools -- recklessly or carefully. The tools of biotech also are affecting the development of one species in particular -- human beings. That's discussed in our final chapter.
|Table of Contents | Chapter 7|
Your Genes, Your Choices is a publication of Science + Literacy for Health, a project of the AAAS Directorate for Education and Human Resources. The publication was funded by the U.S. Department of Energy. The website was built by Mike Wooldridge. Send feedback to SciLit@aaas.org.