Table of Contents
2 Genetic Engineering
Introduction to genetic engineering
The different fields of genetic engineering
3 The problems of genetic engineering
The Flavr Savr®-tomato — The positive consequences of genetic engineering
Designed children — The negative consequences of genetic engineering
What could happen in the future to genetic engineering?
4 Personal Conclusion
There is probably no day going by where we do not see, read or hear one thing about genetic engineering or other news concerning this kind of biological science. Nowadays a lot of scientists work many hours a day to reveal the last of nature’s hidden secrets on how mankind is built. This also reveals many problems!
Some scientists do not hesitate to uncover new facts about genetic engineering in order to patent them and to make as much money out of it as possible. Naturally, this is not helping people who are hoping for a cure of their disease. Others have a horrible dream of the future of mankind being a society that is built up not out of individuals but out of one big brain consisting of men and women with identical looks and thoughts.
Nevertheless, there are advantages of genetic engineering that also have to be mentioned. For example, that with the work of genetic engineering scientists are able to put our insulin producing genes into bacteria and now insulin can be produced in large quantities. That makes life for people suffering from diabetes more comfortable because now they get human insulin instead of pig insulin, which is better for the human body. Without genetic engineering this would have been impossible.
Unfortunately, it is not that easy to decide if products of genetic engineering are good or bad. Right now it is still impossible to determine in how far genetically manipulated products such as food or medicine effect us. They might be totally harmless to humans but they could also cause severe damages within our bodies, which are only seen in the future. We only know that nothing in this field of science really has been proven and tested on a long-term basis. This causes people to argue about advantages and disadvantages of genetic engineering more than ever.
However, is it not necessary to try out genetic engineering before we discard it?
2 Genetic Engineering
2.1 What is genetic engineering?
Genetic engineering is the laboratory technique that scientists perform to change or alter the DNA of a living organism.
To understand what is going on while genetic engineering takes place, it is important to know more of biology and how our genes work:
First of all there are 22 pairs of chromosomes that are like twins in each of us no matter if you are a woman or a man. The difference between women and men lies in two so-called sex chromosomes that we have additionally to these 22 pairs. Women have two X-chromosomes and men have one X-chromosome as well as one Y-chromosome. All together every human being should have 46 chromosomes in each cell of his or her body.
illustration not visible in this excerpt
One chromosome contains DNA (deoxyribonucleic acid) curled up tightly.
DNA consists of two strands each made up of repeating units called nucleotides. These nucleotides consist of one molecule deoxyribose sugar connected to a phosphate group and one of four different bases. Due to the four different bases, adenine, guanine, cytosine and thymine, there exist four different kinds of nucleotides. The nucleotides are connected to a strand by strong bonds that form between the phosphate group of one nucleotide and the sugar of another one. Now two single strands are joined to a double-stranded molecule of DNA by bonds that form between the bases. Each base can only form a bond to one other type of base called complementary base. That is why adenine always bonds with thymine and cytosine always bonds with guanine. The result is a double helix, which resembles a twisted coil. (Picture 1, page 11)
Since we know now how the DNA is built up, we still do not know in which way it contains the genetic instructions. The chemical components are the same in each species but the DNA of one species varies in its quantity and in the order in which the four bases (A; T; C and G) occur along its length from the DNA of every other species. These sequences of bases along the DNA strand are what makes each organism unique.
One of these sequences is called a gene. It contains the genetic information that is responsible for developing the organism’s inherited characteristics. These characteristics are the result of many biochemical processes controlled by enzymes. Enzymes are made out of proteins and each gene carries the information of one special protein’s structure, shape and function. Due to this, one gene produces one enzyme that determines the organism’s inherited characteristics. This knowledge is very important for scientists.
2.2 The different fields of genetic engineering
In the human genome project a lot of scientists try to sequence our DNA to figure out how many genes we have and which gene codes for which characteristic.
This is one requirement for genetic engineering because this field of biological science occupies itself with discharging defected or unwanted genes and afterwards inserts the “right” ones into the organism.
Another requirement is to know how to receive the gene out of the DNA. The discovery that special enzymes can cut and join strands of DNA provides this knowledge. Scientists have learned how to cut specific genes out of a DNA strand and are now able to insert them into other organisms. Later on, they have discovered that vectors, which are little strands of DNA like a virus, could be helpful for their purposes. Vectors are able to infect a cell and insert themselves into its DNA. Scientists now have started to build vectors themselves, which incorporate genes of their choosing and use them to insert genes into other organisms.
Nowadays mostly the DNA of food is altered this way, for example crops that are harmed through crop-eating insects. Scientists knew a long time about an existing microbe that produces a protein that kills crop-eating insects. Today they are able to isolate the protein-producing gene and insert it into the crop plants making the plant’s own tissue poisonous to the insects. This cuts down the use of pesticides, which are harmful to animals and get into our drinking water.
Abbildung in dieser Leseprobe nicht enthalten
Scientists consider not only food as a vulnerable choice of experimenting. In addition, animals have gotten a frequently used portion in genetic engineering laboratories. Since scientists are very interested in improving human’s health, they consider testing on animals as more useful than on plants because several animals have similar body functions to humans.
The biggest issue in genetic manipulation on animals is cloning. Everybody knows the name “DOLLY” and connects it to the case of the sheep that was cloned by the Rosslin Institute in 1996. Cloning seemed to be useful for creating a large quantity of animals with the same favoured features. All it has proved is that this technique it not efficient enough since it took already 217 tries to produce Dolly. Nevertheless, other companies cloned different animals and succeeded.
Scientists predict a future for cloning because it is supposed to make the production of drugs or other medically important substances in animals easier. Domesticated animals can be used to produce for example human proteins or tissues and organs for transplanting. In order to enable an animal to produce such substances it has to be genetically manipulated. Due to this, it costs a lot of time to manipulate the genome of enough animals to provide a substantial amount of the products needed by humans. Cloning could resolve this problem. By cloning the animal that is already altered scientists receive the also altered offspring, which saves them a lot of time. This is only possible if cloning becomes a “normal” scientific technique and is no unstable experiment anymore.
illustration not visible in this excerpt
Genetic manipulation of animals has gotten very sophisticated in the last years and a lot of knowledge that might be used in genetic engineering on humans has been collected. Nevertheless, so far genetic engineering on humans is forbidden by law and even more so by ethics.
So why do we even dream of genetic engineering on humans? There are thousands of answers but the most important one is probably: “To fight diseases!” There are two ways of fighting diseases with genetic engineering. The first is to save babies from inherited diseases by manipulating the gametes of its parents before they join or after. During life though there are certain environmental effects that also damage our DNA. To change these damages scientists could also apply genetic engineering.
3 The problems of genetic engineering
3.1 The Flavr Savr®-tomato — The positive consequences of genetic engineering
Before tomatoes were genetically manipulated, humans used another technique to modify and improve tomato plants. They cross-breaded different tomato plants to get a redder, bigger or better tasting progeny. This kind of enhancing food was practised for thousands of years and never had any critics.
In 1994 the Flavr Savr® tomato made by the company Calgene was the first genetically manipulated food that got the approval of the Food and Drug Administration in the United States to be sold. The tomato’s enhanced feature is that it stays fresh two weeks longer than non-genetically manipulated tomatoes. Critics were raging that this tomato would prove harmful to the consumers and they pointed out that genetic engineering on plants would cause allergic reactions.
Now, almost seven years from the first time Flavr Savr® tomatoes were on the shelves in the supermarkets, it is proven that these tomatoes do not harm anyone. The scientists that were developing Flavr Savr® tomatoes predicted this kind of outcome. Naturally, they were fond of their product but seriously were they not right from the beginning on?
It is easy to judge this opinion right by knowing the background of the Flavr Savr® tomato.
The question that triggered the development of the Flavr Savr® tomato was: ”How can we produce a tomato that stays fresh for a longer time?”
Scientists knew that all fruits posses a gene that produces an enzyme that breaks down the cell walls in ripe fruits. Through this process the fruit turns mushy. The way to enhance a tomato was to somehow switch this gene off. They found a solution by inserting the same gene again into the DNA. In order to understand why this helps and what happens inside the tomato one needs to know a little more about how the process works where genes are translated into the specific characteristics.
As we know one gene codes for one characteristic. The process where the characteristics evolve from the DNA is called transcription. To start the transcription the DNA has to unwind first and through this, the two strands are separated. Then an enzyme retrieves nucleotides and assembles them complementary to the bases of the DNA to form a new strand that is called RNA. This strand is released when it is completed and serves as a mould to form enzymes in so-called ribosomes, the “enzyme factories”. (Pictures 2 & 3, page 12)
In the new Flavr Savr® tomato’s DNA there is the gene for the cell-breaking enzyme that is read and one RNA forms. Then right after the first gene there is the same gene again just the other way around and it is also read. Another RNA forms, which is complementary to the first one. Therefore, these two RNAs attract each other and stick together. These two strands cannot serve as a mould anymore and it is impossible to receive the enzyme. Since the enzyme cannot be produced, the cell walls are not broken down and the tomato stays fresh for a longer time.
This manipulation of the DNA cannot be harmful to us humans in any way. We only eat the tomato and everything including the manipulated DNA is destroyed in our stomach. The only harm this tomato might cause is to other tomatoes. The other tomatoes could inherit the manipulated characteristic from the manipulated tomato during cross-pollination. To prevent cross-pollination, manipulated tomatoes could be grown in tribe houses or on separated fields.
3.2 Designed children — The negative consequences of genetic engineering
The mapping of the human genome shows us all the existing genes. As soon as this project will be finished, scientists will start to study the genes and find out which characteristic they encode. After successfully completing this project, they will start to develop methods to test our DNA and find out if we have a gene that causes for example cancer or Alzheimer disease.
This opens up the possibility to manipulate gametes and therefore the possibility to save our children from suffering from lethal diseases like cancer that lie in our genes. It might seem like a wonderful new development but seen on a long-term basis this might lead to designed children.
In the beginning parents will only demand their children will be cured of lethal diseases, but later they might demand to have children with bigger muscles, specific hair colour, more intelligence or a better ability to remember certain things, which would be possible as soon as we know which gene codes for these characteristics.
Here in Germany and also in other countries the discussion on so-called preimplantation diagnostics is very controversial. The primary function of preimplantation diagnostics is to test the egg cell of a woman right after fertilization and to find out if the new developing individual has any defect or disease causing genes in its DNA. Normally during artificial fertilization more than one egg cell is combined with a sperm. Therefore, scientists receive several fertilized eggs to test. They can now choose which one will be the healthiest and transplant this one into the woman’s uterus for further development.
The problem of preimplantation diagnostics is not the testing itself rather the discarding of the remaining, not wanted embryos. It offends two basic ethical principles: The principle that the life of the embryo has to be saved from the fertilized egg cell on and the principle that offspring is not to be chosen by its quality features. The law here in Germany that has been made to save the lives of embryos does not allow this technique but it neither clearly prohibits it.
Due to this, scientists who will try to carry out this technique might not be saved from court because judges tend to say that even if the laws do not forbid preimplantation diagnostics, ethics do.
Today we already know approximately which gene codes for which disease or malformation. However, there is no such distinctive knowledge as to which gene codes for hair colour or the general outer appearance. Therefore, parents are not able to provide their gametes and then order the child that they wish. Nevertheless, this might be possible in the future. It all depends on the laws that are issued and on how far governmental restrictions let scientists work in this field.
If governments do not issue any laws at all against designed children, consequences might be the development of a two-class society. Not all parents will have the money to pay for artificial fertilization or even for preimplantation diagnostics. Many children will still develop from “normal” sexual intercourse and they will be treated as second-class individuals.
Preimplantation diagnostics might be good as long as it concentrates on banning diseases. However, as soon as it is allowed to design children the conclusion will be that parents are enabled to create children that are superior to others. This could have horrible consequences for mankind.
3.3 What could happen in the future to genetic engineering?
Genetic engineering, which is a wonderful discovery for some and a devilish development of science for others, will continue in the future. Stephen Hawking even said: “Genetic engineering with humans is going to occur whether we like it or not.”
Laws will be issued in every country of the world varying in what they forbid and allow. Nevertheless, scientists will keep on researching and critics will keep on demonstrating against everything that involves genetic engineering.
Genetic engineering has its advantages and disadvantages as we have seen. Since it has not been tested for a long time we do not know which side will end up to be the most powerful one. Sometimes even after testing a new discovery people still do not know if it is good or bad.
An example for this would be the discovery of the splitting of an atom. Many people have died when the nuclear bomb was used or from leaks in nuclear power plants so far. In addition, many people benefited from the easy production of energy by splitting an atom. Even though today we know the consequences of this discovery people still do not agree in one single opinion about it.
The future of genetic engineering might turn out one or the other way. It all depends on what we make out of it and what kind of scientists perform further researches in this field of biological science. If we as the consumers say no to all the food that is genetically manipulated, genetic engineering will not have a future in enhancing food. The same goes for genetically manipulated animals or humans. If mankind decides that this is not wanted, genetic engineering will die out. On the other hand, as soon as people are willing to try out food or are willing to accept an organ from an animal, genetic engineering will be kept alive and it will grow and get better within a short time.
4 Personal Conclusion
Since I have been collecting information about genetic engineering I have tried to think of the future and what will happen to us if we keep on researching in this field of science. I am probably a little bit subjective because I am very interested in genetic engineering but after all, I have concluded that for me genetic engineering is acceptable.
I know about the negative side effects of genetic engineering and I also see that they can be severe. I just hope we will never get that far.
Therefore, I am only saying yes to genetic engineering when it is done with care and concerning ethics and human rights. In my opinion, there have to be strict laws that say exactly what is to be done and what not. It has to be impossible to find a loophole in these laws. Scientists have to be watched closely and if they are breaking the laws, there have to be hard penalties.
It will be hard to establish similar laws worldwide, since it is already hard to do this for one country. Nevertheless, this is the only way to keep scientists who have no scruples from doing harm to any organism. Without worldwide laws scientist could leave a county where it is forbidden to do what they want to do and start again in another country. Unfortunately, in third world countries many more problems have to be solved first before they can even think of issuing a law about genetic engineering. Therefore, it will take its time to make safe rules for the whole word considering genetic engineering.
However, without such boundaries I would not want to see anyone manipulating plants, animals or even humans.
- Picture 1— The double helix
illustration not visible in this excerpt
- Picture 2 — Transcription Picture 3 — “enzyme factory”Ú
illustration not visible in this excerpt
PSRAST (Physicians and Scientists for Responsible Application of Science and Technology) -What is genetic engineering?
Scientific American - Cloning hits the big time
Geenor – Home page
Geenor – Why genetic engineering is advantageous for mankind
E-Magazine – Designer People
Lemaux, Peggy G., Ph.D - A Tomato is a Tomato, or Is It?
Consumer Acceptance of Genetically Engineered Food — A U.S. Perspective
Smith, Deborah – Ban on designer babies ‘may be lifted’
Turning Point Project – Who plays God?
Catenhusen, Wolf-Michael – Präimplatat http://www.catenhusen.de/themen/gentechnik/praeimplantationsdiagnostik.html
The role of micro organisms in genetic engineering
...and the biology LK 2000/2001
Towle, Albert; Modern Biology. (Toronto: Holt, Rhinehart and Winston/ Harcourt, Brace, Jovanovich)
 GEENOR home page: http://www.geneticengineering.org/