Download Genetic Technology Discussion

(5/4) Bellringer:
Biotechnology
1.
2.
What do you know about the
following topics?
 Stem cell research
 Genetically modified
organisms (GMOs)
 Gene therapy
 Cloning
Do you think humans have
gone too far in terms of
“Playing God?” Explain!
Gene Therapy
 A technique for correcting defective genes that cause genetic
disorders (what are some examples of genetic disorders?)
 A vector is used to deliver the therapeutic gene to the patient.
 Currently, the most common vector is a virus that has been genetically
altered to carry normal human DNA. Small bacterial chromosomes called
plasmids are also used.
 The genetic code is UNIVERSAL!
 Target cells that express the mutation are “infected” with the
viral vector. The vector then injects its genetic material (DNA or
RNA) containing the therapeutic human gene into the target cell
 The viral DNA then becomes a part of the cell’s genome,
replacing the mutated gene, and the cells express the gene
Cell Transformation
Recombinant DNA
Host
Cell
DNA
Target gene
Modified Host Cell DNA
Restriction enzymes like EcoRI cut
DNA into fragments
Fragments from different
DNA cut by the same
restriction enzymes can
form recombinant DNA
Gene Therapy

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Pros
Treatment of a genetic
disease for which there is no
treatment
Potential for life-long
treatment from a single
injection (a cure)

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Cons
Autoimmune response
Viruses may target the wrong
cells
May be inserted into the wrong
location in the DNA
May lead to the development
of a tumor
(5/5) Bellringer
1.
2.
What is a DNA fingerprint? If
you don’t know, take a guess.
Some mafia gangster robbed a
bank, and then inexplicably left
blood and semen everywhere
for CSI to analyze. Based on
this DNA fingerprint, who
dunnit?
Transgenic Plants/Animals (GMOs:
Genetically Modified Organisms)

Introducing new traits into
organisms using recombinant
DNA technology
Bacterial transformation using restriction enzymes and
plasmids
Recombinant
DNA
Gene for human
growth hormone
Gene for human
growth hormone
Human Cell
Bacterial
chromosome
Sticky
ends
DNA
recombination
DNA
insertion
Bacteria cell
Plasmid
Bacteria cell
containing gene for
human growth
hormone
Transgenic Plants/Animals (GMOs:
Genetically Modified Organisms)

There are several methods for introducing genes into plants
and animals:
 infecting plant cells with viruses or plasmids as vectors
carrying the desired gene (like in gene therapy)
 “Gene guns” can “shoot” the host cells with particles of
DNA.
 Cells may be treated with chemicals to make plasma
membranes more permeable—DNA diffuses in.
 Electroporation—a short electric shock creates temporary
pores in membranes, and DNA can enter.
Transgenic Plants
Gene to be
transferred
Agrobacterium
tumefaciens
Inside plant cell,
Agrobacterium
inserts part of
its DNA into
host cell
chromosome.
Cellular DNA
Recombinant
plasmid
Plant cell
colonies
Transformed bacteria
introduce plasmids into plant
cells.
Complete plant
generated from
transformed cell.
Transgenic Plants (GMOs)

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Pros
Improved Nutritional Quality (Ex:
adding vitamin A to rice)
Eliminate pesticide use
Biopharmaceuticals: the genes for
proteins to be used in human (and
animal) medicine can be inserted into
plants and expressed by them
Greater yields

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Cons
Endangering native species
Unknown health risks
“Genetically contaminate"
wild populations, non-GMO
farms, and ecosystems
Environmental pollution from
overuse of herbicides
Evolution of stronger, more
resistant species (e.g.,
weeds, pests)
Insect Resistance
Herbicide Resistance
80% of processed foods in the U.S.
are genetically modified

Pharming: production of
pharmaceuticals in farm animals or
plants
 Ex: Transgenes are inserted into
fertilized eggs of sheep next to the
promoter for lactoglobulin—a
protein in milk.
 Transgenic animals are raised that
produce large quantities of the
desired protein (e.g., human
growth hormone) in their milk
Fertilized eggs
containing the
transgene are
implanted into
females who give
birth to transgenic
offspring
Human protein is extracted from the
milk to be administered to patients
Transgenic animals: Taiwan breeds fluorescent green pig
The transgenic pigs, commonly used to study human diseases, would
help researchers monitor and trace changes of the tissues during the
physical development
“FOR THE FIRST TIME,
RESEARCHERS EDIT THE
GENES OF HUMAN EMBRYOS”
 Rumors that this research was
underway turn out to be true
Cloning


Making an exact copy of an
organism by using its DNA
Somatic Cell Nuclear Transfer: a
nucleus containing DNA is inserted
into an “empty” (enucleated) egg cell.
Then the embryo is implanted in a
surrogate who will carry the fetus to
term and deliver a new offspring
(clone)
Cloning
Donor Nucleus from udder cell
Electric shock fuses cells
Fused cell
Egg Cell
Nucleus
removed
Embryo
Cloned
Lamb
Foster Mother
Cloning
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Pros
organ transplant
propagation of animals facing
extinction
produce skin, cartilages, and
bones to save the victims of
burns and accidents
produce cells to cure cancer, or
repair the retina, or the spinal
column
Cons
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ETHICS
Has not been perfected
yet
Health risks from
mutation of genes
Animal clones have had:
 shorter life expectancy
 liver failure
 compromised immune
function
 tumor growth
The Island
Stem Cell Research

Stem cells have the potential to differentiate into any type of
specialized cell in the body
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Totipotent stem cells can form an entire organism
Pluripotent stem cells can form any type of cell but not an entire
organism
Induced pluripotent stem cells result from dedifferentiating cells
 Cultured iPS cells have been used for cell therapy in animals
Research aims to heal injuries and disorders in which cells are lost and
cannot be replaced (Skin Gun)
Somatic cell nuclear transfer can be used to culture stem cells
Stem Cell Research

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Pros
Can be used to treat
diseases which
currently have no
cure
replacement cells
and tissues/organs

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Cons
Come from human
embryos with the
potential to grow
and develop
ETHICS
DNA Fingerprinting
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Everyone has a unique DNA “fingerprint” (nucleotide sequence)
A person’s DNA is the same in every cell
Procedure:

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DNA is extracted from cells and mixed with restriction enzymes which cut
the DNA at specific sequences
Gel electrophoresis: DNA fragments are exposed to electrical current
and separate leaving a unique pattern…a DNA “fingerprint”
 DNA is negatively charged so it moves towards the + end
 Short fragments of DNA move faster and farther
 Fragment patterns can be compared from DNA samples taken from
different individuals
Gel Electrophoresis
DNA Fingerprinting
Pros

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DNA is unique from person to
person but the same from cell to
cell in one person
Paternity and Maternity
Criminal Identification and
Forensics
Personal Identification
Wildlife Management
Cons
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Invasion of privacy
(ETHICS)
Genetic disorders could
affect life and health
insurance premiums
Do you want to know if
you have a genetic
disorder that will strike
in middle age?
DNA fingerprinting = CSI
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Smaller
fragments move
faster/farther
Thicker bands
contain more
copies of that
fragment
(5/6) BR
1.Who are the parents of the soldier?
2. The murderer’s blood was found on the victim, and
blood was found at 2 possible crime scenes. Where
did the murder take place? And who did it????