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project is based on this hypothesis:
How may genetic engineering
help us to find solutions to medical diseases/disorders?
paper is an interesting journey through the mysteries of the natures own
miracel; genetic engineering. We chose this subject because we wanted to get to
know more about the future of genetics. This is quite new area in medicine,
therefore we had some difficulties finding information. We had to look through
scientific literature, and search the net. Once again the web has helped us
writing a paper. Reading this paper you will get an introduction to different
aspects of genetic engineering. We decided to begin our paper with an explanation
of genetic engineering because it is the basis for the rest of our project. You
will also read about diseases/disorders caused by errors in the DNA, and how
they may be treated. We chose to write include cloning because it is a new way
of treating diseases/disorders. In the end we have som prospective aspects on
the subject. We hope you will enjoy our paper.
Stian, Are, May, and Sadia
This is a way of changing the inherited
characteristics of an organism in a predetermined way by altering its genetic
material (Microsoft Encarta’95). This is often done
to create microorganisms, such as bacteria or viruses. This is done to synthesize increased yields of compounds, to form
entirely new compounds, or to adapt to different environments (Microsoft
Encarta’95). Genetic engineering also includes gene therapy. This
technology is used in the treatment of
people with cancer and AIDS (Acquired Imune Defciency Syndrome).
Engineering involves the manipulation of
DNA (Deoxyribo Nucleic Acid). Important tools in this process are so
called restriction enzymes. These are produced by various species of bacteria.
Restriction enzymes can recognize a particular sequence of the chain of
chemical units, called nucleotide bases, that make up the DNA molecule , and cut off the DNA at a
wanted location. Fragments of DNA generated in this way can be joined by using
other enzymes called ligases. Restriction enzymes and ligases therefor allows
the specific cutting and reassembling of portion of DNA.
this very complicated process of copying, errors might occur. This means that a
«c» or a «t» could switch places, and create a new combination in the DNA
structure. This is called a mutation.
is what Darwin based his theory of evolution on - mutations makes slight
differences in the inherited material, and can in the long run create different
other thing that is also very important in the manipulation of DNA, are so
called vectors. These are pieces of DNA that can produce copies of themselves
independently of the DNA structure in the host cell where they are grown.
Examples of vectors include plasmids, viruses, and artificial chromosomes.
way one cell will always be able to produce as big quantities as wanted. The
process of engineering a DNA fragment into a vector is called cloning. Multiple
copies of an identical molecule is produced .
way, recently discovered, of producing many identical copies of a particular
DNA fragment is polymerase chain reaction. This method is fast, and avoids the
need for cloning DNA into a vector.
benefits of genetic engineering are many. For example it can be used to make
artificial insulin. Insulin is normally found only in higher animals, but by
using genetic engineering it is now possible to «grow» insulin in bacterial
cells. The bacterial cells can easily be produced in any wanted quantity, and
makes the insulin much more available.
can supply us with knowledge about diseases yet to come, and «errors». Both
concerning us and our unborn children. The use of these tests creates several
questions, both ethical and
fundamental. And they confront us with fundamental questions: Do we want to
know or not?
genetest can be made at any time in the life of a human being, also during the
fetus stage. The results of the tests are not dependent on the persons medical
condition. Since the genes are inherited, one will also be able to tell if relatives
will inherite the same disease. Genetests may also in some cases tell if a
person is carrier of a gene that may strike his or hers children as a
congenital and chronicle malfunction or disease.
diseases are caused by genetic errors. These diseases belongs to different
Sex related diseases:
that affect boys and girls in different ways, because the gene which leads to
the disease is on the X-chromosome, if one of the mothers X-chromosomes
contains the defect gene. Her children will have a 50% chance to inherit this
gene. Her daughters will usually just be carriers, while her sons will get the
disease. The daughters other X-chromosome, which they inherit from the father
will produce enough normal protein to increase the effect from the defect
gene-copy, so they will be protected in the same way as their mother. An
example of a sex related disease is hemophilia.
Not sex related recessive diseases:
of the parents have to be carriers, and each of them need to have a copy of the
gene which is defected. The parents don’t have the disease because they have a
“healthy” gene too. If both of the parents are carriers the chance for the
children to be carriers is 50%, and to get the disease will be 25%. An example
of a none sex related recessive disease is Cystic Fibroses.
Not sex related dominant diseases:
defects which are inheritable from both parents, the children’s chance to get
the disease is about 50%. An example of a not sex related dominant disease is
A sick person and a healthy person
having a child, have a 50 - 50% chance of getting a sick/healthy child
Mellitus is a disease caused by defective carbohydrate, and characterized by
abnormally large amounts of sugar in the blood and urine. Diabetes can damage
the eyes, kidneys, heart and limbs. It could also endanger pregnancy.
disease is classified into two types:
I: Insulin dependent diabetes mellitus (IDDM), this type is called
"juvenile onset diabetes" because it occurs in children and young
II; Non-insulin dependent diabetes mellitus (NIDDM), this type is called
"adult onset diabetes", because it’s usually found in persons over
the age of 40.
human pancreas secretes a hormone called insulin. The insulin takes the sugar out of the blood, and stores it. When a person has diabetes, the problem is
almost always a total or severe reduction of insulin.
was first obtained in 1921 from the pancreatic tissue of dogs. "In 1981
insulin made in bacteria by genetic engineering became the first human hormone
obtained in this way to be used to treat human diseases."
("insulin", Microsoft Encarta) Today they use insulin from pigs. The
human body accept this insulin because it’s almost the same as a human insulin.
Diabetes with transplanted cells
about 15 years ago, the form of diabetes that usually strikes children and
young adults was invariably lethal. Families and physicians watched helplessly
as the victims died within weeks or months of diagnosis. By the early 1900s
investigators knew that the problem lay
with small clusters of pancreatic cells called the islets of Langerhans. These
islets normally secreted a critical hormone, later named insulin, that enabled
other cells to take up the sugar glucose from the blood for energy. It was also
obvious that in the diabetic patients ( today said to have type I ) insulin production
had ceased. Consequently, glucose from food accumulated in the blood while
other tissues starved. People with the more prevalent, later onset form of
diabetes ( type II, or non-insulin - dependent ) managed far better because
they continued to make at least some insulin.
for type I diabetics improved dramatically in the early 1920s, when insulin
extracted from animals proved lifesaving. For decades thereafter most people
assumed daily injections of the hormone were tantamount to a cure. Unfortunately,
they were mistaken. Over the years clinicians gradually came to realize that
many patients eventually suffer from potentially devastating diabetes - related
disorders. Microscopic blood vessels can slowly become damaged, often
culminating in blindness or kidney failure, or both.
key to ensuring long-term health, is to provide therapy that can maintain
glucose values within normal limits at all times from the start of the disease.
An ideal treatment would be implantation of islets, because functional islets
would restore proper insulin production and, in theory, would have to be
implanted only once; native islets survive for many years and carry within them
the precursor cells needed to supply replacements for cells that die.
Successful grafts would also avoid acute diabetes-related illnesses. These
conditions include coma induced when glucose accumulates to extremely high
levels in the blood, as well as insulin reactions (often marked by shakiness,
confusion or blackouts), which arise when an injected dose of insulin lowers
glucose levels too far. Islet transplantation is conceptually simple but has
been difficult to implement. Finally, however, there is good reason to think
this potentially curative therapy will be available to many patients within the
next five years and will become routine for newly diagnosed patients within a
few years thereafter.
engineering will help us humans with several unsolved mysteries. What can it do
for us when it comes to cancer? But first of all, what is cancer? Cancer is new
growth of tissue because of abnormal cells which invade and destroy other,
healthy tissue. It is cells which is not under the body’s control anymore
because of malfunctions in the DNA or genes. Almost all cancers form tumors,
which is many abnormal cells that clings together. The three major types of
cancer are sarcomas, which appear from bone, nerves, bloodvessles, muscles and
fat. The second one is called carcinomas. It is the most frequent form of human
cancer. It arise from epithelial tissue, like skin and the lining of body
cavities and organs. The third type is called leukemia and lymphomas. They
involve blood-forming tissue. They invade for example the bone marrow.
might also be wondering about what causes cancer. It is a difficult question,
but basically one can say it is a genetic process. It is changes in the genes
or DNA caused by heredity, viruses, ionizing radiation, chemicals and changes
in the immune system. There is not one thing which causes cancer, but a series
of things happening. That’s one of the reasons it is hard to protect oneself
are many ways to treat cancer, but no treatment is 100% reliable. There is not
a drug one can take and get healthy. To treat cancer it has to be discovered at
an early stage. Doctors have to regularly examine persons who are in the high
risk group( smokers, other in family with cancer, people who sunbathe a lot).
The most used treatments are:
Ť radiation therapy
one goes through a surgery the whole tumor is removed. That way the surgeon
hopes to get rid of all the abnormal cells. The use of radiation therapy is
effective. The body is exposed to ionizing radiation which one hope will kill
the abnormal cells. The last few years one has found out that expotion to
radiation only weakens the cell so the p53 gene will activate the cells suicide
mechanism. Another discovery is that radiation therapy may also in fact be
fatal for the patient because if the p53 gene isn’t healthy it won’t kill the
abnormal cells, and the tumor will grow. The last treatment is chemotherapy.
With the use of drugs one kill the cells by interfering with DNA
gene which kills cancer - p53
1979 two scientists named David Lane and Arnold Levine discovered a new gene,
p53. At the time it didn’t create any speculations because it seemed to cause,
not kill cancer. Some years later, in 1989, Lane and Vogelstein did an
extraordinary discovery. p53 kills tumors. They found out that if p53 is
healthy it keeps the cell it is in normal, but if it is absent, damaged or tied
up by other molecules, it may create cancer. “p53 acts as the cell’s director of damage control. A healthy cell
usually keeps a small number of p53 proteins around, continuously degrading
them and replenishing the supply. But if something - ionizing radiation, a
chemical carcinogen, chemotherapy drugs - damages a cell’s DNA in a way that
threatens to set in on the pat of cancer, the cell switches into high alert. If
everything is working right, something signals the p53 to stop degrading, and
tells it that it’s time to be active”. (Newsweek, January 13th 1997, page 38)
p53 cell switch off a damaged cell, so it can restore itself. When it is
restored p53 turn the gene on again. This way it prevents tumors. p53 can also
kill a cell by activating its suicide mechanism. The p53 gene is good for
humans when it’s healthy, but when it’s damaged it may be a factor in creating
cancer. The gene may be damaged when it mutates or is affected by chemicals. If
so happens the p53 gene will stimulate cell division rather than suppress it.
It also turns on a new set of genes which makes cells immune to cancer drugs.
someone inherit a mutant p53 gene, and not any healthy p53 genes, they are most
likely to die fast of cancer. Most p53 mutations are not inherited though. They
arise from copying errors and affect by chemicals, for example cigarette smoke.
One mutant gene is enough to create a deadly tumor.
the discovery of the p53 gene one found out how the body itself treat cancer.
In the last few years scientists have experimented with different approaches to
find a cure to cancer. One hope to be able to provoke p53 genes to attack
abnormal cells. Scientists have succeeded in isolating isolate white bloodcells
that will kill cancer, and they have found proteins that will train the immune
system to attack tumors. In this way they might be able to develop a vaccine.
Today there are a dozen in development. The naturally produced white blood
cells (T-cells) attack proteins it doesn’t recognize. Scientists inject
proteins from cancer cells into patients, and that will activate the immune
system. In this way they might be able to develop a vaccine. Today there are a
dozen in development.
vaccines are different from the ones used to prevent diseases. Cancer vaccines
are supposed to treat diseases which already exists. Still there is a long way
to go before there will be a cancer vaccine on the market.
is a new discovery, and there isn’t much information about it. First experiments on human beings started in
the late 1980 `s.
one use genetherapy one supply a functional gene to cells lacking that
function. In that way one hopes to correct genetic disorders (Genetic disorder
is loss of a gene in the DNA. You can only get it by heritage, for example
Huntigtons syndrome and Cystic Fibrosis) or acquired diseases (cancer).
Insertion of a gene can be used to correct an inherited genetic defect, to
counter or correct the effects of a gene mutation, or to program a cell for an
entirely new function or property.
There are two ways of genetherapy:
Ś alteration of germ cells
(sperm or eggs)
Ť somatic cell transplant
of germ cells will result in permanent genetic change for the whole organism
and the following generations. This way of genetherapy is not an option because
of ethical reasons.
repair/replace defect genes with healthy ones. It’s done in three ways:
if the genetic inheritable disease is in the
man’s sperm the procedure can be done before the egg is fertilized.
the same procedure can be used on women’s eggs.
if it shall be done on a fertilized egg, it has
to be carried out within a few hours after the conception.
cell transplant is synonymous with organ transplant. Doctors take some blood
from the spinal marrow, bring the blood to a laboratory and add healthy,
correct genes. Then the blood is injected into the artery. One hope that the
bloodcells with the healthy genes will start to divide themselves, and convey
the body with loads of fresh DNA. Then the body will heal. The defect DNA will
still be in the body, but the immune system will be restored by the healthy
DNA. So far scientists can only treat diseases which is caused by an error in
one gene. They cannot correct several genes at the same time.
time genetherapy may provide effective treatment of many diseases and
disorders, including cystic fibrosis, muscular dystrophy, and juvenile diabetes.
Scientists also tries to find a way to treat disorders which not are inherited.
An example is AIDS. Scientists are doing research on how to make cells
genetically resistant to the infection which AIDS causes.
clone is an organism, or group of organisms, which is derived from another
organism by an asexual (non-sexual) reproductive process. The word clone has
been used about cells as well as organisms, which means that a group of cells
stemming from a single cell is also called a clone. Usually the members of a
clone are identical in their inherited characteristics, which means they have
identical genes, except of course for any differences caused by mutation.
Identical twins, for example, are members of a clone, they originate from the
division of a single fertilized egg, while non-identical twins are not members
of a clone because they originate from two separate fertilized eggs. A number
of simple organisms, such as bacteria, many algae and some yeasts, and even
some higher organisms, for example flatworms and plants such as the dandelion,
reproduce by cloning. So cloning isn’t something that humans created, but in
recent years advances of genetic engineering has brought us beyond the natural
limit and in to a new era.
can now isolate an individual gene (or group of genes) from one organism and
grow it in another organism belonging to a different species. The species
chosen is usually one that can rapidly reproduce asexually, such as yeasts and
bacteria. Because they multiply so fast, these methods makes it possible to
produce many copies of a particular gene. The copies can then be isolated and
used for the purposes of study, for example, to investigate the chemical nature
and structure of the gene, or for the purposes of medicine, for example to make
large quantities of a useful gene-product, such as insulin. This technique is
called cloning, because it uses clones of organisms or cells. It has a great
medical potential and is the subject of active research. Identical-twin animals
may be produced by cloning too. An embryo in the early stage of development is removed from the uterus and split,
then each separate part is placed in a surrogate uterus. Mammals such as mice
and sheep have been produced in this way since 1986.
development has been the discovery that a whole nucleus can be taken from a
cell and injected into a fertilized egg, whose own nucleus has been removed.
The division of the egg brings about the division of the nucleus, and the
descendant nuclei can, in their turn,
be injected into eggs. This cloning technique is in theory capable of producing
large numbers of genetically identical individuals. Such experiments have been
successfully carried out with frogs and
mice, but the cloning of higher mammals beyond an early embryonic stage
has been considered not possible. Until recently. On January the 23rd this
year, 1997, the whole world was presented to Dolly, a sheep produced by
cloning. And she was produced through a totally new and revolutionary method.
The nucleus was removed from a mature
egg, and the «emptied» egg was then «melted»
together with a normal cell through an accurately calculated electric
shock. The result was one living egg cell with the genes from the normal cell,
which acted like a fertilized egg. The egg was then placed in a uterus and
after the certain amount of time, Dolly was born, identical to the one the
normal cell belonged to, and with no father. Technically, there is no reason
why this technique shouldn’t be used to clone humans. But it is a tough ethical
issue. A lot of people are afraid that someone will misuse this knowledge to
their own benefit. But on the other hand, cloning may help us find solutions to
inherited diseases. (See appendix for more information on human cloning)
and future prospects
all have our dreams of an utopia. A society without problems, disease,
pollution. What you know are going to read is yet just another dream. It’s just
philosophical thought on how genetic engineering might be used in the future.
it comes to genetic engineering, you can’t avoid the ethical dilemmas. Genetic engineering is a very vulnerable
issue because it may affect every living thing on this planet. A lot of people
are afraid of what it may lead to in the future, while some just think of the
possibilities to find solutions to every disease known to man kind.
engineering may be the solution to many diseases/disorders, such as cancer,
aids, inherited disease and to diseases/disorders caused by genetic «errors».
There isn’t any solutions for those today. But do we know that the information
we get will be used in the right way? We’ve already seen that knowledge may
lead to things that are highly thought-provoking. We can now find out if people
suffer from, for example Downs syndrome before they are born.
that you are in year 2200. You are blind. But hey, don’t worry. Scientists have
made a biological computer which they operate into your brain. It gives you
your sight back. Just by mixing some genes together scientists make anything.
Cancer and AIDS are defeated. A cure was found years ago.
you’re pregnant and you really want a blond, medium sized, smart, funny boy you
just go to the hospital and tell them. There you’ll get a list of all the
characteristics you want to give your child. Well, it costs, but when you
really want a bright boy who cares? Or if you want a pretty girl just let them
the food. Let’s say you don’t like carrots. Then you just buy carrots which
tastes like chocolate or strawberries or whatever you like. You’ll get all the
vitamins, but it tastes whatever you want it to taste! Isn’t that great? Say
you have beef, carrots, potatoes and brown sauce for dinner. It’s healthy, but
you don’t like potatoes or brown sauce. Well, buy it with apple taste. Cool.
Your children will love dinner! Not to mention how easy it will be to “keep the
food”. By mixing lettuce with some of the genes from pine it will stay crispy
and green forever. Isn’t this the society we all dream of? Or is it?
it be cool to eat beef, potatoes, carrots and brown sauce when it all tastes
like chocolate? What’s the point of getting pregnant if you may decide on how
your child shall be. There will be no excitement raising your child. If we
exterminate all diseases, won’t there come another which is worse in time?
Think about it. Genetic engineering may do so much, but do we want all of it?
Shouldn’t there be a limit?
has two sides. All of the above is crazy
stuff genetic engineering may lead to, but what may it do for us when it
comes to medical issues? One example is that it may exterminate genetic
differences like the Downs syndrome. Normally a person has 23 pairs of
chromosomes, a person with Downs syndrome has one pair to much. The syndrome
may be exterminated by removing the two extraneous chromosomes during labor. If
the baby turns out to have the syndrome, the mother automatically have the
right to have an abortion, even after the twelfth week.
engineering can also give us solutions on how to repair mutations in the DNA.
By repairing these mutations doctors will be able to cure gene based illnesses.
We have already mentioned the Downs syndrome, but it also includes all forms of
cancer which is inheritable.
engineering has good and bad sides. We will have to compare both sides and
decide on which side we like the most. But it all ends up in ethical questions
like “do we want a society without diseases and people with handicaps”, and “
do we have the right to decide who gets to live and who doesn’t”?
engineering leave us with a lot of possibilities, but few answers. Where do we
draw the line? How will we know when to stop? Will we in the future see a
society with no illnesses, a perfect world, or will we have a society where
only the ones with perfect genes can benefit from social security, insurance,
loans and so on. Will they become someone important? Maybe there will be fought
wars to get access to the newest information. Maybe we will have world wide
viruses that kills most of us because there is no genetic variation, a result
of cloning. Maybe none of this will happen. Nobody knows, all you can do is
we have the opportunity to clone. But what are the consequences? This is the
most debated issue. Many people say that they are against all genetic
engineering, because we don’t know were it might lead. When the train was
invented people said the same. Some of us will always be afraid of the new and
unexplored, while others blindly look at the possibilities.
engineering is a puzzle - one never knows where the next piece shall be placed.
There are many ways to treat diseases/disorders with the help of genetics.
project has given us many answers to our hypothesis. We have learned how
genetherapy may treat non-functional genes, and we have seen how genetic
engineering can help us treat diseases of today. We think of genetic
engineering as a thing of tomorrow. We learn more as every day goes by.
though it can do “wonders” there are some dangers lurking behind the tree. An
example is the potential dangers of cloning. Genetic engineering may also in
the end make humans resistant to antibiotics. There are many ethical dilemmaes
which still needs to be debated. There are no answers, just questions! This is
why it is important that everybody get involved. All of us have to decide on
whether or not they support the progress.
last words will be what President Clinton so elegantly put it:
Don’t play God!
The Cancer Letter
Time - the cloning breakthrough
oss tukle med naturen” by Elin Brodin
University of Oregon
- nye muligheter, nye dilemmaer” by Bioteknologinemda
Newsweek Jan. 13th 1997, Jan. 27th 1997
i genalderen” by Kristin Aalen Hunsager/Audgun Oltedal, Samlaget 1988
enn gener - utredning om bioteknologi og menneskeverd” by Kirkerĺdet 1989
og genteknologi - er det noget for os?” by Kaskalot Pćdagogisk Sćrnummer 1992
Microsoft Encarta’95 (Cd-rom)
Norske leksikon” by Ascheoug og Gyldendal