GENETIC ENGINEERING. - Instituto Bachiller Sabuco

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11 Δεκ 2012 (πριν από 4 χρόνια και 6 μήνες)

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GENETIC ENGINEERING.

Genetic engineering is used to take genes and segments of DNA from one species and
put them into another species.
To do so, genetic engineering provides a set of techniques to cut DNA either randomly
or at a number of specifics sites.
Once isolated one come study the different segments of DNA, multiply
them up splice them (stick them) next to any other DNA of another cell or
organism.
Genetic engineering makes it possible to break through the species
barrier and to shuffle information between completely unrelated species.

Genetic engineering aims to re-arrange the sequence of DNA in gene
using artificial methods. To determine the DNA sequence on such a long
chain, a high speed, low-cost method is needed. Unfortunately, the currently available
method (gel-electrophoresis) does not satisfy these requirements. It cannot provide
sufficient information about the genetic structure.

What benefit could genetic engineering bring to humankind?
Some scientists believe that since genetic codes determine the appearance,
personality, health, and aging process of human beings, if that genetic information in the
chromosomes could be decoded and the genetic mechanism were understood, we
could potentially control and improve our health, quality of life, and the biochemical
processes in our bodies. In other words, we could control our own fate. Also, we’d be
able to improve the genes of other animals and vegetables so that they could serve
humankind better. At first sight, these ideas seem reasonable and attractive. However,
careful analysis reveals that they are based upon an incorrect theory- the theory of gene
determinism.




1 What is cloning or cloned?
Cloning is to duplicate a cell or an organism, usually asexually, which is genetically an
exact replica of the other cell or organism.
Cloned is a cell or organism reproduced by cloning.
Algae, fungi and plants can reproduce sexually as well as asexually and can be cloned
in the laboratory.
Most higher animals form clones naturally only when identical twins occur.

Cloned
In multicellular organism, all the cells come from the same fertilized egg cell.
DNA is a cell copy, which come from mitosis. Mitosis is a
process which produced two daughter cells from a fertilized
oocyte, is a cells division.
Each cells contain identical genetic material, they carry the same
number chromosomes and genes. In genetic, all the cells of the
multicellular organism- except sperm cells and egg cells –are
clones.
During embryonic development, the embryo can assume
different shapes and functions.
The cells assume function and characteristics specifics. In
mammals, for example, red blood cells carry oxygen; skeletal muscle cells contract and
move the body; and nerve cells conduct electrical impulses that signal other cells to
respond.
The genes come from different cells combinations. One combination of active and
inactive genes results in a skeletal muscle cells. A different combination of active and
inactive genes result in a nerve cell.




2 What is a clone?
A clone is a cell or an organism that is genetically identical to another cell or organism.
Many simple organisms are clones because their reproduction is asexual.
During the process of sexual reproduction, the nucleus of a sperm cell combines with
the nucleus of the egg cell and the resulting embryo carry genetic material from both
parents and it isn’t identical to its parents.
The verb “to clone” refers to the process of creating cloned cells or organisms.
In cloning experiments with cattle and mice, the “donor” chromosomes came from early
embryos.
Early embryos from mammals are called blastocysts, balls of immature cells that are
produced after a fertilized egg divides several times, but before any specialized tissues
begin to develop.

How cloning is done in animals?
Step 1: Take any cell of adult animal’s body.


Step 2: Take an ovum, from the ovary of any adult
female.

Step 3: Take the nucleus out of the egg cell.

Step 4: Put together the first cell and the ovum
without nucleus. It will start to multiply forming a
microscopic ball of many identical cells.

Step 5: In about six days place it in the uterus of the
Female.
Step 6: In nine months a baby will be born just like
the adult animal, without any genetic characteristic of
the female who gave the ovule and lent the uterus.
3
Cloning of an animal.
In 1996 researches lead by Ian Wilmut of the Roslin Institute near Edinburgh, Scotland;
cloned a sheep, from the mammary cells of an adult sheep, and in July 1996, Dolly was
born.
This event market the first time a mammal had been cloned.
The scientists, led by Wilmut of the Roslin Institute, based their techniques in methods
developed in the 1960s by Gurdon, Briggs and King.
They experiment with the American clawed frog, Xenopus laevis. They used the nucleus
tadpole’s intestinal cell to generate an adult frog.
Dolly could cause an international uproar because she isn’t an ordinary sheep; she is a
clone (an exact genetic copy of her donor “mother”).
That event has produced debates among researchers, ethicists and politicians.
It is important to understand what the process of cloning involves and why Dolly is so
special.
As early as the 1950s scientists used the same techniques to clone amphibians as frog
and salamanders.

How was Dolly created?
The Dolly’s creation is possible owing
Ian Wilmut and his collaborators.
Dolly was created from the cells
derived from the cells of a six years
old sheep.
The adult cells combine with the
oocyte, which was ready to be
fertilized.
Previously, the scientist had taken off
the nucleus from the oocyte and
combines it with the other cell by an
4 electrical current.
From that is created the embryo.
The resulting embryo, which became Dolly, carried all of the chromosomes from the
donor cell. So, Dolly is an exact genetic copy of the donor cell, Dolly is a clone.

Why did researchers create Dolly?
Two biotechnology companies funded the reach.
PPL Therapeutics is trying to find ways to produce animals that carry certain proteins in
their milk. The theory is that if researchers can develop animals with desirable
characteristics.

Why is Dolly so special?
In Scotland, the scientist tried 277 times to create cloned sheep, and they created only
one: Dolly. They are trying to
perfect the techniques used in
Dolly’s creation.
Dolly is special because she
proves that cells from an adult
animal aren’t too specialized to
generate a new organism.
Researchers thought that the
genes in adult animal are turn off (inactivation) and the genes in the fertilized egg or a
young animal are turned on (activation) and can create a new organism.
Dolly proves the mistake of scientists.
“Dolly was cloned from an adult, somatic cell”. A somatic cell is a cell that carries the full
number of chromosomes for that species. Somatic cell such as muscle cells, nerve cells,
and skin cells are usually specialized to perform certain functions.
Some researchers think that Dolly may have resulted from a cell with characteristics of
embryonic cells.
During pregnancy, cells in mammary tissue like Dolly’s donor “mother” are capable of
developing into different kinds of cells.
5 Dolly proves that it’s possible to clone a healthy animal from the nucleus of an adult cell.

Why was Dolly a success?
To prepare the donor cell, Wilmut and his collaborators removes cells from the udder of
a pregnant sheep, and grew them in plastic dishes in incubator.
To understand how Dolly was created, it’s necessary to understand the normal cell
cycle.
The cell cycle is a series of molecular events that allows a cell to reproduce
itself.
In division cells, the cell cycle progresses through four phases: mitosis or cell
division (M), a cell-growth phase called “gap” 1 (G1), a period of DNA
synthesis in which the DNA replicates itself (S), and a second “gap” (G2) in
which the cell prepares to divide.
The nucleus of the udder cell used to generate Dolly was arrested in G0, which allowed
it to reprogram to form an embryo.
Researchers know that the cytoplasm of an oocyte contains proteins that encourage
embryonic development. In the case of Dolly, some of the proteins in the egg cell
cytoplasm reprogrammed the nucleus of the udder cell began to behave like the nucleus
of the fertilized egg.
After the cell divided several times and became a tiny ball of cells called blastocyst, the
researchers placed it into the uterus of an adult female sheep.
The sheep carried Dolly through a normal pregnancy when Wilmut and his collaborators
analysed the DNA of Dolly’s cells, they found that it was identical to the DNA of the
donor cell. That is why Dolly is a clone.

GENETIC ENGINEERING OF OUR FOOD.
Health risks.
-Already a genetically engineered food supplement has killed 37 people and disabled
1500 others.
-New toxins and allergens in food.
6 -Horizontal gene transfer and recombination could result in creating new pathogenic
bacteria and viruses.
-We could waste our defence against disease.
-Spread of virulence among pathogens across species by horizontal gene transfer and
recombination.
Environmental risks.
-We could be looking at the end of the world, as we know it.
-New plant viruses could develop from genetically engineering crops that are virus
resistant.
-Major insect pets could envolve bio-pesticide resistance.
-“Genetic pollution” by self-replicating genetically modified organisms is irreversible.
Benefits.
-Biotechnology is needed to feed the growing population of the world, especially the
Third World.
-Reduced chemical inputs, which will be good for the environment.
-Higher yields, benefiting farmers and consumers.
Other aspects.
-Some transgenic food.
Potatoes, corn, soy, canola oil, cotton seed oil, yellow crook-
neck squash (gene-spliced with an two experimental viruses
and arbitrary marker genes. Targeted for baby food) and
tomato products, papaya.
-Eat only organics rennet less cheese.
Most (75%) non-organic cheeses are made with genetically engineered rennet called
chymosin.
-Other genetically engineered additives and enzymes.

Healthy cells. Transplantation.
Cancer.
Cancers, for example, are clones of cells inside an organism because they consist of
many replicas of one mutated cell. If just one chromosome of one of your cells changes
7 genetically because of radiation or simulation or heat, that cell become a cancerous
tumour when starts to multiply.
Clone is also an organism, which is genetically an exact replica of another organism.
Singled-celled organism, such as bacteria, protozoa, and yeast, usually reproduce
clones asexually. Clones of these organism are useful is research, for example to test
drugs and other compounds, because all the test bacteria have the same genetic
makeup, and differences in effectiveness among the different drugs result from the drug
itself and not from the bacteria which are exactly the same.
Hopkins Researchers find genetic Colon Cancer Change in healthy cells.
John Hopkins scientists have found a genetic alteration associated with common forms
of colon cancer in parents’ normal cells. The same abnormality, called loss of imprinting
(LOI), also appears, the researchers say, in a significant number of healthy people,
offering a possibility of predicting as many as 40 percent of new colon cancer cases
before they start. ”It’s the first cancer-related genetic alteration found at high frequency
in healthy people”, says Andrew P. Feinberg. By contrast, the known colon cancer
genes that predict high risk of the illness, together account for less than 3 percent of
new cases.
In the study, the Hopkins team analysed both tumours and normal parts of the colon in
30 patients with colon cancer, looking for loss of imprinting (LOI)-refers to an abnormal
switching-on or off of genes. People inherit copies of the same gene from both parents,
and both genes and sets of genes work in tandem in a person’s cell.
In normal development, in a process called imprinting, the copy from one parent, in
certain genes, is turned off. This inherited preferential silencing usually holds throughout
all cells in a person’s body.
Because of a new study we know a second defect in the actual cancers. This defect,
called micro satellite instability (MSI), involves an unusual duplication of certain
stretches of DNA-a sign of glitch in the way DNA reproduces or repairs itself.
With these discoveries we know more of the problems, which causes cancer. Knowing
where are the problems and the mutation in the genes, we could prevent this illness.
8 Thanks to the genetic engineering we could modificate the mutation, and the wrong
genes, and the strange changes of DNA and we could evite the cancer and other illness,
which transmit from parents to their children.

Xenotransplantation.
Xenotransplantation is the transplant of animal organs into human. Is a multi-billon dollar
business venture built on the anticipated sale of patented techniques and organs. It has
received strong criticism and opposition from scientist warning of the risks of new
viruses crossing from animal organs to human subjects and from there to infect the
population at large. Scientific reports of virus crossing from pig to human cells
(transgenic pigs) and of viral infections in humans.
Thanks to it we can transplant healthy organs in human body with ill organs.

Discussion
Two important questions:
-Can adult humans be cloned?
Probably yes, but not in the hear future, because even the achievement of the Roslin
Institute has not been duplicated yet neither in the Roslin Institute nor in any other
laboratory.
-Should humans be cloned?
A Time Magazine poll in March 10, 1997 reported that 74% of those asked believe it is
against God’s will to clone human beings. Humans’ cloning is illegal in England and
Norway, but not illegal in the US. However, in the US federal are privated funds not
prohibited.
Agree and disagree opinions:

Agree:
-Many of the achievement of modern medicine are consequence of the scientific
advances. For example, heart transplants and test-tube babies select healthy cells to
avoid cancers or other genetic illness, … those had not been possible without the news
technology.
9 -What is about the human soul? In the test-tube babies the human immortal soul is
created and inserted by God at the moment of conception, when the sperm and ovule
unite, just like any normal conception. In the possible human cloning, the immortal
human soul would be created and inserted by God at the moment of conception, when
the cell of the donor is united with the ovule.
-Cloning could provide a genetically identical replacement for a lost loved one, or for a
baby born with birth defect. Some people are already saving pieces of their skin or other
organs of loved one’s. They are already several organ banks doing the job of freezing
living organs for the future.
-A clone would be in the family as well as any other members, and he would have as
much of a sense of individuality and rights as do identical twins.

Disagree:
-With the actual techniques many humans will come out severely deformed. Over 270
attempts were needed before Dolly was born. Many fetal lambs did not survive the early
stages of development; most of those carried to term were born with severe birth
defects. Hence cloning an adult sheep was extremely difficult to do. And the experiment
of Dolly has not been duplicated in any laboratory since 1996.
-Cloning is not playing God: Cloning merely produces life from existing life. Cloning can
be though of as an extension of procedures like in-vitro-fertilization.
-Cloning might lead to the creation of genetically engineered groups of people, like Hitler
or Einstein, or athletes, or strong or beautiful people…it might lead to an attempt to
improve the human race according to an arbitrary standard. And this might be true.
However identical twins or cloned humans do not result in equal human characteristics,
because the environment and upbringing play a large role in shaping someone’s
emotions, character and outlook. One clone raised in poverty without education, with
hunger and the sun of Africa, would be a totally different person than the clone raised in
opulence, with good education, in Boston. The time and place of living are very
important. A theoretical Einstein clone today would probably not become a world
recowned physicist. So you can’t get the clone that you wanted.
10 -A clone is against the traditional concept of family and he may have fewer rights than
other people.




OUR GENETIC FUTURE
What will it be like in a future world where your life started with your parents designing
your genes?
In addition to screening for unwanted genetic diseases, they select for sex, height, eye,
hair, and skin-colour.
You could choose a special temperament, intelligence, mindfulness, and perhaps sexual
orientation.
You may be genetically engineered to be an enhanced clone of one of your parents, or
of a celebrity whose genetic heritage your parents have purchased at great prize.
If your parents are pouring, they may be paid to design you with genes tailored for a
particular occupation, together with a pre-birth contract for future employment.
As in the film “Gattaca”, you probably belong to a clearly defined social class according
to the degree of your genetic enhancement.
Of course there may still be a few weird, unenhanced naturals by choice living in the
mountains.










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BIBLIOGRAPHY.

Searchers:
www.yahoo.com
www.lycos.com
www.excite.com
www.altavista.com
www.britannica.com

Addresses:
http://science-education.nig.gov/nibHTML/ose/snapshots/multimedia/ritn/dolly/index.html
http://science-
education.nig.gov/nibHTML/ose/snapshots/multimedia/ritn/dolly/moredolly.html
http://biblia.com/sex/cloning.html
http://hopkins.med.jhu.edu/newsmedia/press/1998/NOVEMBER/981103.HTM
www.bio.ub.es/genetic/GENEAEGA3.htm
www.netspeed.com.au/cogs/coggene.htm
www.sfsu.edu/~rone/gedanger.htm
www.green.org/s-r/20/20-01.html
www.argonet.co.uk/users/john.roser



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INDEX.

Genetic engineering…………………………………………………………………….1
What’s cloning or cloned?………………………………………………………………2
Cloned…………………………………………………………………………………….2
What’s a clone?………………………………………………………………………….3
How cloning is done in animals?……………………………………………………….3
Cloning of an animal……………………………………………………………………..4
How was Dolly created?…………………………………………………………………4
Why did researchers create Dolly?……………………………………………………..5
Why is Dolly so special?…………………………………………………………………5
Why was Dolly a success?………………………………………………………………6
Genetic engineering of our food…………………………………………………………6
Healthy cells. Transplantation……………………………………………………………...7
Discussion …………………………………………………………………………………9
Our genetic future…………………………………………………………………………11
Bibliography………………………………………………………………………………..12


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