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Gene Technology
Biotechnology
A. This technology uses living organisms and new
techniques to produce things people need.
B. Biotechnology has provided scientists with new
methods of mapping genes. By a technique
Polymerase Chain Reaction (PCR), millions of
copies of minute DNA fragments can be made in a
matter of a few hours. C. Today scientists use PCR
to quickly make many copies of selected segments
of the available DNA. With PCR, a scientist can
produce a billion-fold increase in DNA material within
a few hours.
D. Genetic Engineering also known as Recombinant DNA
Technology and Gene Splicing is a technology that allows
strands of DNA to be transferred from the cells of one organism
into cells of another organism. New traits can be introduced into
embryonic cells using this procedure.
1. This technology uses a procedure for cleaving (cutting) DNA
from an organism into small fragments, and inserting the
fragments into another organisms of a different species.
2. This technology gives scientists the ability to alter the genetic
material in an organism by changing its genes or by combining its
genes with those from another unrelated organism. The altered
DNA is called recombinant DNA which is DNA made by
connecting fragments of DNA from different sources.
3. Transgenic are organisms that contain functional recombinant
DNA. In other words, they have foreign DNA in their cells.
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II. Steps Used to Produce a Transgenic Organism:
A. Isolation of the foreign DNA fragments to be inserted
and the cutting.
B. Both the DNA from the organism containing the gene of
interest (insulin gene) and the DNA from a vector are cut. The
DNA is cut by a restriction enzyme.
C. Transgenic Animals: It carries a trait that the scientist would
like to transfer to another organism. The gene may be inserted
into an organism to improve its quality (disease resistance in
tomatoes) or to “trick” bacteria and yeast into producing useful
human proteins (interferon, vaccines) or hormones (insulin,
growth hormone). D. Recombination of genetic material occurs
constantly in nature, but gene splicing makes it possible for the
scientists to carry it out in a controlled fashion in the laboratory.
For this reason, the end result is frequently called “genetic
engineering”.
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EX:
Restriction Enzymes (DNA Cleaving
Enzymes): Bacterial proteins (enzymes)
that have the ability to cut both strands of
the DNA molecule at certain points.
Example: EcoRI is a restriction enzyme
that makes staggered cuts in the double
strands of DNA leaving sticky ends.
Cut
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G A A T T C
C T T A A G
Cleavage
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E. Making Recombinant DNA -- The joining
of the DNA with a vehicle to transport it.
F. **Once DNA has been cleaved, the fragment
can be inserted into a host cell. In order to
produce recombinant DNA, the cleaved fragment
of DNA must recombine with something else.
That something else is a vector.
G. Vector is an agent that is used to carry the
gene of interest into another cell.
H. Examples of biological vectors: viruses,
mosquitos, and plasmids.
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I. Plasmid is a small ring of DNA found in a bacterial cell. It carries
different genes from those of the bacterial chromosome. Plasmids
can replicate independently of the main chromosomes of bacteria.
The plasmid can be cleaved with restriction enzymes. If the plasmid
and the foreign DNA have been cleaved with the same restriction
enzyme, the sticky ends of each will match and they will join,
reconnecting the plasmid ring. The foreign DNA is recombined into
a plasmid or viral DNA with the help of a second enzyme.
J. After the foreign DNA has been spliced into plasmid, yeast, or
virus vector, the recombined DNA is transferred to a host cell.
When the host cell prepares to divide, it copies the recombinant
DNA along with its own DNA. The process of making extra copies of
recombinant DNA is a form of cloning. Clones are genetically
identical copies. Cloning is the process that is called gene
cloning. Cloning process through which scientists create genetically
identical organisms.
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K. Screening —Cells that have received the particular
gene of interest are distinguished, or screened, from the
cells that did not take up the vector with the gene of
interest. This process is called screening. Each time
the cells reproduced, they make a copy of the gene of
interest (insulin gene).
L. **Gene cloning is an important step in the process
of genetic engineering because multiple copies of
desired DNA are produced.
M. Recent experiments include splicing a human gene,
such as the gene for insulin, into the DNA of bacteria.
N. Since bacteria reproduce so rapidly, it is possible to
mass produce large quantities of bacteria that can
produce human insulin. Drug manufacturers use
genetic-engineering techniques to produce certain
drugs, such as insulin and
human
grown hormones.
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III. Applications of DNA Technology—Genetic
Engineering in Medicine and Society
A. How is this technology of use to humans?
Many species of bacteria have been engineered to
produce chemical compounds that are of use to
humans.
Example: create oral vaccines by putting
vitamins into fruits and vegetables.
GMOs-Genetically Modified Organisms
B. The 3 main areas proposed for transgenic
bacteria
1. Agriculture
2. Biotechnology
3. Medical
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Bacteria used in genetic
engineering
1. Agriculture —One species of bacteria has already been
used successfully on agricultural crops.
a. Plants have been genetically engineered to produce
internal pesticides.
b. Strawberry crops are engineered to resist frost damage.
c. They can engineer fruit to be sweeter or firmer or a
different color.
d. Recombinant or Transgenic Organisms —Organisms that
contain functional recombinant DNA. They contain foreign
DNA in their cells. Another way in which gene technology is
used in animal farming is in the addition of human genes to
the genes of farm animals in order to get the farm animals
to produce human proteins in their milk. This is used
especially for complex human proteins that cannot be made
by bacteria through gene technology. The human proteins
are extracted from the animals’
milk and sold for
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pharmaceutical purposes.
2. Biotechnical —in industry, transgenic
bacteria have been engineered to break
down pollutants into harmless products.
a. Example: A bacterium capable of
breaking down oil. These transgenic
bacteria are used with some success in the
Gulf of Mexico to clean up an oil spill off the
coast of Texas.
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3. Medical- The way this technology could be useful in the practice of
medicine is the prevention of inherited disorders. In medicine,
pharmaceutical companies already are producing molecules made by
transgenic bacterial species to treat human disease.
a. Examples: Transgenic bacteria are employed in the production of:
1. growth hormone to treat dwarfism.
2. Tissue plasminogen activator (dissolves blood clots after MI/CVA)
3. human insulin used to treat diabetes.
4. A vaccine is a solution containing all or part of a harmless version of a
pathogen (disease-causing microorganism). When a vaccine is injected,
the immune system recognizes the pathogen’s surface proteins and
responds by making defensive proteins called antibodies. In the future, if
the same pathogen enters the body, the antibodies are there to combat
the pathogen and stop its growth before it can cause the disease.
5. Developing clotting factor VIII (for hemophilia)
6. Human lung surfactant (premature babies)
7. Atrial natriuretic hormone (hypertension)
8. Bovine growth hormone (increase cow’s milk production)
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Geneticall
y
engineered
“blue” rose
Genetically
engineered
neon fish
Genetically
engineered
cartilage for
prosthetics
Genetically
engineered
organisms
Genetically
engineered
tobacco plant
Gene technology &
Bioremediation
**Genetically engineered bacteria that return environment
back to natural state.
Cloning
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Reproductive cloning involves the transfer of
genetic material of a donor cell into an egg
cell that has had its DNA removed.
The egg is stimulated by chemicals and
electricity to cause it to divide (cytokinesis)
It is implanted into the uterus of a female to
develop in the placenta.
The cloned parent is genetically identical to
the original parent.
Scientists are developing ways to use clones
to save endangered species….what do you
think about human clones???
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Cloning??
Injaz, camel
SNUPPY,
afghan
hound (2005)
*Most recently cloned
3/8/2009
Dolly,
sheep
(1996)
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The Human Genome:
A genome is the total
number of genes in
an individual.
A Chromosome map is
the genetic map that
shows the location of
genes on a
chromosome.
Human Genome Project:
 1. The potential for gene technology to help fight
against disease is great, one of the most
significant efforts to include the usefulness of
gene technology is the human genome project.
 2. It is the major effort to map and sequence all
human genes by the year 2003.
 3. The goal is to create maps showing where
every gene is located on human chromosomes.
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4. As chromosome maps are made they are used
by:
a. Diagnosis of genetic disorders:
Many genetic disorders occur when an individual
lacks a functioning copy of a particular gene.
There are improved techniques for prenatal
diagnosis of human disorders. A few cells are
obtained from a fetus or from the fluid surrounding
the fetus and tested for genetic disorders.
b. The next step after diagnosis is gene therapy.
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Gene therapy:
i. It is the insertion of normal genes into human cells to
correct genetic disorders.
ii. Possibly in the next decade we’ll see the use of DNA
technology to cure genetic disorders. This is done by
injecting a healthy copy of a gene into a person with a
defective gene.
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c. DNA Fingerprinting
i. DNA fingerprinting is a technique which is being used to identify the
source of human DNA in paternity cases and criminal cases. Sources
of DNA samples include not only blood but also skin, semen, saliva
from a cigarette butt, or hair roots which are used in forensic cases.
Blood has DNA only in white blood cells because they contain a
nucleus with DNA. RED BLOOD CELLS IN THE BLOOD STREAM DO
NOT HAVE DNA BECAUSE THEY DO NOT CONTAIN A NUCLEI!
b. In criminal cases, analyses would be performed on DNA samples
from the crime scene and on suspects. A search for matching band
patterns would be made. Positive results can be used as evidence in
court if the laboratory has followed a strict chain of custody
procedures. In a paternity case a comparison is made between the
child’s DNA and both parents. Bands in the child’s DNA must be found
in either the mother’s or the father’s DNA
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c. Law-enforcement workers use unique fingerprint patterns to
determine whether suspects have been at a crime scene. In the
past ten years, biotechnologists have developed a method that
determines DNA fingerprints. DNA fingerprinting can be used to
convict or acquit individuals of criminal offenses because every
person is genetically unique.
d. It is also possible to manipulate DNA by cutting it into pieces
with enzymes and running it through a gel substance using an
electric current. This process is called gel electrophoresis.
e. Electrophoresis is used to separate and sequence DNA
fragments by charge and length which identify genes or organisms.
This process is often used to compare a sample of DNA found in
tissues collected at a crime scene with the DNA of the suspect. Cut
DNA is separated into segments of different lengths during the
process of electrophoresis.
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Do the remaining bands match the father?
No
Analysis of DNA Fingerprinting in Forensic Testing
Did the suspect leave the evidence at the crime?
No
This diagram shows what a sample gel
with DNA bands would look like.
Do the remaining bands match the father?
Yes
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