We have now taken a quick look at the components of cells and how they work. We have also looked at DNA and cell genetics. Our next question might be "so what"? Is this information important to us, either personally, socially, or in regard to business?
The answer is a strong YES! Several of the most important scientific advances of today--and some of the biggest controversies--involve genetic engineering. With genetic engineering DNA--the stuff that is the blueprint for a particular organism--is change. In some cases this may just involve one organism. In others, it could mean that an entire family is changed in some way, either for better or for worse.
First, however, we need to clarify a few points. "Genetic engineering" has been going on for thousands of years, in the form of plant and animal breeding. People breed plants and animals to improved one or more characteristics. An example is the dog: all dogs, from chihuahuas to German shepherds, are derived from one "primordial dog", probably some sort of wolf. Over time humans have bred dogs until we have all of the breeds of today, many of which can't really live without human help.
Plants have also changed: wild carrots, for example, used to be purple. Now only orange ones are thought to exist, and these are almost all in gardens, not wild. Similarly, common ginger is cultivated through cuttings now, not through seeds.
What makes genetic engineering so interesting is that we no longer have to simply use breeding. Instead, we can more or less directly modify the genetic makeup of a cell. We can even add or remove things. For example, fire fly genes were added to tobacco plants, resulting in fields that glowed in the dark! This could not have been done with "natural" methods, because you can't breed a firefly and a tobacco plant.
Some people make it sound like genetic engineering is, or will be, a solution to all sorts of problems, including world hunger. Others claim that it is incredibly dangerous, and that we could accidentally wipe ourselves out and/or ruin the environment. The truth (as with many new technologies) is probably somewhere in between.
We might loosely distinguish between two broad types of genetic engineering: "inside" and "outside." While they actually use many of the same methods, people's reactions vary to them.
"Inside" genetic engineering means that what is going on takes place totally in a laboratory or refinery. For example, we learned earlier that alcohol is made through a process of fermentation: we put some yeast in a vat along with some nutrients (sugar water), and wait. We end up with a mix of alcohol, sugar water, and yeast. The yeast and water are thrown away and/or refined out, leaving only the alcohol and water.
Many other products are also produced through fermentation. Penicillin, for example, is made by putting some bread mold in a vat with nutrients. After a while the mold and nutrients are refined out, leaving only the antibiotic penicillin, which can then be processed into pills.
With genetic engineering, our yeast or mold is modified genetically to produce more of the same product, or perhaps a different product. However, the fermentation process is still the same, and it all takes place in a laboratory. In fact, if some of the genetically modified organisms get away (say, down a drain), they will probably not survive very long because they have been designed only live in a lab setting. Thus, people don't mind this "inside" form of genetic engineering as much, because it is carefully controlled.
Accidents do happen, however. One example of this took place at Showa Denko, a chemical manufacturing plant in Japan. They were making tryptophan, an amino acid that is also used as a dietary supplement.
Tryptophan is normally produced through bacterial fermentation. Showa Denko produced a culture of bacteria that could produce even more of the product than usual.
The problem was that the genetically engineered organisms produced not only tryptophan (which they were supposed to), but also traces of other similar chemicals as well. These contaminants were so similar chemically to tryptophan that they passed through the refinement process. Unfortunately, the contaminents were also quite poisonous, resulting in 37 deaths and 1500 more people becoming totally disabled.
As soon as the problem was discovered, the company destroyed their cultures. Unfortunately, this made it impossible to be 100% positive that the problem was with the genetically engineered cultures, or with the refinement process. However, most specialists think that it was in fact the bacteria. Furthermore, Showa Denko ended up with 2 billion dollars worth of lawsuits.
The point here is NOT to show that products produced using "inside" genetic engineering are more dangerous than conventional engineering. Rather, it is to show that, as with any other new product or process, real risks exist. The same can also be said for any other (non-genetically engineered) product or drug placed on the market.
Note, too, that there are many drugs either have been approved by the U.S. Food and Drug Administration, or are in the FDA approval process, which are produced from genetically modified organisms. These include drugs for use in treating AIDS, anemia, cancer (leukemia and colo-rectal), cystic fibrosis, hemophilia, diphtheria, hepatitis B and C, human growth hormone deficiency, and multiple sclerosis.
The other form of genetic engineering is "outside genetic engineering." Here, plants or animals are produced with are then released into the environment in the form of crops or food animals. Once released, they are much harder to control 100% of the time, so this form of genetic engineering is even more controversial than "inside" genetic engineering when it comes to commercial products. ("Inside" genetic engineering for commercial purposes is generally not as controversial. However, there is a lot of controversy when it is used for military purposes to create new or more powerful disease-causing agents!!)
The goal of genetic engineering in this context is, of course, to produce more and better food crops and meat animals. So far, however, the results have been problematic.
Many of the new genetically engineered crops have not actually been modified for reasons of food quality output. Instead, about 40% have been designed for herbicide tolerance. This means that people can use more weed killers without hurting their crops. The problem here is that this may lead to more weed killers being used, thus contaminating the water supply and also leaving more spray on the crop plants.
Another use is to produce crops that are resistant to pests, so that plants produce their own internal pesticides. When a bug bites into the plant, it is either repelled or poisoned. While this seemed initially attractive--least bug sprays are being dumped into the environment, and people need to spray less--there are problems. First, plants that have been engineered to be poisonous to bugs may also cause side effects in humans. Second, helpful bugs may be killed as well; one study found that over half of the monarch butterflies that ate pollen of a genetically modified plant plant died. Finally, the pest bugs may become tolerant to the plant poison fairly rapidly.
So far, relatively little work has been done to actually increase the quality or vitamin content of crops. Worse, there is some chance that genetically engineering plants could produce more plant viruses (plant diseases) than it cures, though the jury is still out on this.
Some also object to the "patent problem." Many crops now are hybrid crops, requiring farmers to buy new seed each year. Genetically improved crops could "breed true," so that farmers could save seed and not buy more. However, genetically modified crops and animals "breed true"--the seed could be replanted again, and the animals can be mated to breed more animals. However, if the genetically modified plant or animal is patented, farmers could be required to pay a royalty to continue using the seed, even though they harvested the seed themselves. Similarly, they could be forced to pay royalties if they breed genetically engineered animals. Farmers and cattlemen generally dislike this.
Another problem is that of interbreeding. What happens if some of the genetically modified plants or animals get away--as is quite likely--and breed with wild species, introducing genes into the wild that would never occur there naturally? Could humans accidently produce the equivalent of Killer Bees-some particularly robust plant or animal pest that is difficult to control or manage?
Finally, there is another serious problem that we have to face. Suppose we take, say, a tomato plant and insert genetic material from, say, a peanut plant. There may be no environmental risk involved here. However, there may be human risk, if a person eats the tomato who is happens to be strongly allergic to peanuts. To guard against this would require that every tomato from the field be tracked and/or labeled--a huge task, which would probably be impractical on a large scale. This is the "labelling controversy."
There are other uses for genetically engineered crops that may be less objectionable, however. One example could be genetically engineering animals, such as goats or cows, to produce products (such as human insulin) in their milk. The slang term for this is "Pharming." Many people have less problems with this (as long as the animals are being treated with reasonable care), because here the animals are fairly well controlled and are not physically hurt in the production of the product.
Other forms of genetic engineering are also on the horizon. Cloning is a hot topic now, in the wake of the cloning of Dolly the Sheep in Scotland. While some are concerned with animal cloning, what really stirs people up is the prospect of the cloning of humans. While this has (probably) not happened yet, there are several problems, both technical and social:
1. Remember, we get our mitochondria from our mother, and these are not coded for in the DNA of the cell nucleus. It appears that "Dolly Jr." has 7-year-old mitochondria when born. Nobody knows what effect (if any) this would have for sheep--or for humans. There could also be other factors which don't work quite right, either.
2. So far it does not appear that anybody can prove that they have cloned a human being to the point of birth. However, this could happen in the not-too-distant future. If scientists do manage to clone a human and can avoid the "old mitochondria" and similar problems, it might not be much more "unnatural" than an identical twin is today--however, the end result would be an infant, not a full-grown adult. Thus, if one of us were cloned it would be like having an identical twin, only it would be a baby rather than being our own age.
However, other problems emerge:
This sort of genetic repair is the dream of many researchers today, though it will probably take a long time for us to be able to do it. While few would argue with fixing something that is clearly defective (like muscular dystrophy or cystic fibrosis), some are concerned that we might try to improve on nature. Would it not be temping to, say, pay somebody a few thousand dollars and increase the chances of having a child with, say, good math skills? Or improved musical talent? Or a better memory? Many are uneasy with the prospect of "designer children," in part because it may place undue burdens on the children ("I paid thousands of dollars for you to be a pianist, so you better become one!!), as well as causing social problems. (What if the rich are the only ones who can afford the "improvement" technology?)
A final use for genetic technology could be "xenotransplantation." This is the notion that we could engineer animals (such as pigs or chimpanzees) to produce entire organs (such as hearts or livers) suitable for transplantation into humans. What sort of ethical problems (if any) might emerge here? (This is actually already done on a very small scale using non-genetically engineered parts; right now about 60,000 pig heart valves are transplanted into humans each year!)
Sources:
"Whose Genes? Tiki the Penguin's Guide to Genetic Engineering" http://www.oneworld.org/penguin/genetics/home.html This is an easy-to-read overview of the promise and risks of genetic engineering. While aimed primarily at children, the content is very good.
"The Big Issues" http://dspace.dial.pipex.com/srtscot/bigissue.htm The Church of Scotland's Science, Religion, and Technology Project site. Contains much informative material on genetics, and also looks at the ethical implications of many of the technologies.
"Tryptophan Summary" http://www.psrast.org/jftrypt.htm A synopsis of the Showa Denko poisonings.
"Biotech Pharmaceuticals and Biotherapy: An Overview" http://www.ualberta.ca/~csps/JPPS1(2)/biotech.htm A list of drugs produced through genetic engineering that have received FDA approval.
"Traits Introduced Into Crops by Genetic Engineering" http://www.psrast.org/geprodct.htm An overview of some of the traits that have been introduced into crop plants. Generally critical of genetic engineering.
"The Virus Hazard" http://www.psrast.org/virhaz.htm An overview of the possibility of new viral plant diseases being introduced though genetic engineering. Generally critical of genetic engineering.
"Designer Seeds" http://www.beyonddiscovery.org/content/view.article.asp?a=167 The National Academy of Sciences' look at genetic engineering of crop plants. Generally favorable toward genetic engineering.
"List of Genetically Altered Foods" http://www.icta.org/legal/biolist.htm A list of genetically altered food plants produced during the 1990's, along with their manufacturers.
"Poison Plants? Genetically Modified Crops, Grown Over Much of the U.S., Remain Controversial" http://www.sciam.com Scientific American article examining the controversies and risks surrounding genetically modified food plants.
"Medical Transplantation," Microsoft® Encarta® Online Encyclopedia 2004
http://encarta.msn.com An excellent overview of the current state of organ transplantation.