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Genetic Engineering
• Genetic engineering: Changing the DNA in
living organisms to create something new.
• This organisms are called Genetically
Modified Organism (GMO)
• Example:
• Bacteria that produce human insulin
• Genetically Modified organism are called
transgenic organism; since genes are
transferred from one organism to another.
Some genetic engineering techniques are
as follows:
1. Artificial selection
A. selective breeding
B. hybridization
C. inbreeding
2. Cloning
3. Gene splicing
4. Gel electrophoresis: analyzing DNA
1. artificial selection: breeders choose which
organism to mate to produce offspring with
desired traits.
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They cannot control what genes are passed.
When they get offspring with the desired traits,
the maintain them.
Three types of artificial selection:
A. selective breeding
B. hybridization
C. inbreeding
A. Selective breeding: when animals with
desired characteristics are mated to
produce offspring with those desired traits.
• Passing of important genes to next
generation.
• Example: Champion race horses, cows
with tender meat, large juicy oranges on a
tree.
• For example people breed dogs for specific
purposes.
• Dachshund were once bred to hunt badgers
and other burrowing animals.
• They must be small to fit into the animals hole
in the ground.
• Selective breeding occurs when you choose the
best male and female to breed.
• This allows you to fine tune and control the
traits
• The offspring or babies will then have the best
traits.
• Then you continue to breed those organism
with the best traits, those traits will be
maintained.
• Examples of
selective breeding:
• Angus cows are bred to
increase muscle mass so
that we get more meat,
• Egg-Laying Henproduces more eggs
than the average hen
• B. Hybridizations: two individuals with unlike
characteristics are crossed to produce the best in both
organisms.
• Example: Luther Burbank created a disease resistant
potato called the Burbank potato.
• He crossed a disease resistant plant with one that had
a large food producing capacity.
• Result: disease resistant plant that makes a lot of
potatoes.
Other Examples of hybridization:
1. Liger: lion and tiger mix
2. Grape + apple= grapple. The fruit
tastes like grapes and looks like apple.
C. Inbreeding breeding of organism that
genetically similar to maintain desired
traits.
• Dogs breeds are kept pure this way.
• Its how a Doberman remains a Doberman.
• It keeps each breed unique from others.
• Risk: since both have the same genes,
the chance that a baby will get a recessive
genetic disorder is high.
• Variation: difference between
individuals of a species.
• The differences are in the
genes but we see the
physical differences.
• For example: Some humans
have blond hair and some
have brown. This is a
variation among humans.
• Some finches have short
beaks, some have long
beaks.
• Inbreeding decreases
variations.
2. Cloning: creating an organism that is an
exact genetic copy of another.
• There are human clones in our school.
• identical twins are naturally created
clones.
• Clone: group of cells or organisms that
are genetically identical as a result of
asexual reproduction
• They will have the same exact DNA as the
parent.
How is cloning done?
► A single cell is removed from a
parent organism.
► An entire individual is grown from
that cell.
► Remember one cell has all the DNA
needed to make an entire organism.
► Each cell in the body has the same
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Dolly:
Dolly was the first
mammal cloned.
She had the same exact
DNA as her mother and
had no father.
Cloning is a form of
asexual reproduction.
Only one genetic parent.
http://content.tutorvista.com/biology_11/content/media/cloning.swf
• Since Dolly, cats and other organisms have
been cloned.
• The cat that was cloned had the same
exact DNA but different color fur than the
mother.
• How can this be?
• Environment plays a huge part in the way
organisms develop.
• Eggs are haploid
• Haploid: half the
chromosomes, 23 in
humans
• Body cells are diploid:
• Diploid: two sets of
chromosomes, one from
mom and one set from
dad 46 in humans.
How could you clone
a human?
• Step 1: An egg is
removed from a female
human
• Eggs are haploid: 23
chromosomes.
• The nucleus of the egg
is removed and is
thrown away.
23
EGG CELL
• Step 2: A body cell is
removed from another
person.
• The nucleus of the
body cell is removed
• Body cells are diploid:
46 chromosomes.
46
Body Cell
• Step 3:
• The nucleus of the
diploid body cell is put
into the egg.
• This egg no longer
needs to be fertilized
since it has all 46
chromosomes.
46
EGG CELL
• Step 4: The egg is then
charged with electricity to
start mitosis.
• Step 5: Its then put into a
surrogate mother so it can
grow.
• Its going to be genetically
identical to the parent of the
body cell.
• But it will be a baby.
• Plants and animals can be
cloned.
Click and clone
• http://learn.genetics.utah.edu/content/tech/cloni
ng/clickandclone/
Benefits of cloning:
1. you can make exact
copies of organisms
with strong traits.
2. Increase food supply
3. Medical purposes:
clone organs for
transplants.
4. Bring back or Stop
species from going
extinct.
Saber Tooth Tiger extinct
Risks of cloning:
1. Decreases genetic
diversity
2. If one of your clones
gets a disease, they all
get it: same immune
system.
3. Inefficient: high failure
rate: 90%+
4. Expensive
3. Gene splicing: DNA is cut
out of one organism and put
into another organism
• A trait will be transferred from
one organism to another.
• For example: the human
insulin gene can be removed
from a human cell.
• It can be put into a bacterial
cell.
• The bacterial will now make
human insulin.
• This picture represents gene splicing.
• However, DNA is much smaller.
• Its done with high tech lab equipment since
DNA, is too small to hold or see without a
microscope.
The red piece the woman
is holding is an insulin
gene from a human
being. It is being
combined with DNA from
a bacteria.
Creates recombinant
DNA, something that has
never existed before.
Benefits:
• insulin is cheaper
• There are no side
effects because it
is human insulin.
• We once used pig
insulin but there
are side effects
and it more
expensive.
How are genes cut for gene
splicing?
• A bacterial plasmid is used.
• Plasmid: circular DNA in a bacteria
cell.
• It is very simple and easy to
manipulate.
• A restriction enzyme: enzyme that cuts the
DNA at a specific code.
• There are thousands of restriction enzymes.
• Each cuts DNA at a different sequence.
• Some look for GGCC and cut in between the G
and C.
• Every time GGCC is found in the DNA it is cut
by the restriction enzyme
DNA Code:
• TTATGGCCATACGGCCTT
• AATACCGGTATGCCGGAA
• TTATGGCCATACGGCCTT
• AATACCGGTATGCCGGAA
• TTATGG
• AATACC
CCATACGG
GGTATGCC
CCTT
GGAA
• This DNA segment was cut twice creating three
fragments.
• Since every one is different, we all have a
different amount of times GGCC is found.
• My DNA may be cut seven times
• Yours may be cut ten times.
This is how a restriction enzyme
works
How is gene
splicing done?
1. A restriction
enzyme cuts the
insulin gene out of
the human DNA.
2. A plasmid is
removed from a
bacteria and cut
with a restriction
enzyme
3. The human gene is place into the bacteria
plasmid
4. The plasmid is placed back into the bacteria.
• The cell now has directions (DNA) to make
insulin.
• That's exactly what it does.
• Its human insulin, bacteria do not make insulin
on their own.
Plasmid with
insulin gene
• This is called transformation: when a gene
from one organism is transferred to different
organism.
• The organisms that have DNA transferred to
them are called transgenic organisms.
• trans: means different,
• genic: refers to genes
• Genetic engineering has given rise to a new
technological field called biotechnology
(technology of life).
1. Transgenic (GMO) animals: genes
inserted into animals so they produce what
humans need.
• Why?: A way to improve the food supply:
A. Transgenic cows: gene inserted to
increase milk production.
B. Spider goat: gene from spider inserted
into goat.
• Goats makes silk of the spider web in their
milk.
• Flexible, stronger than steel. Used in
bullet proof jackets.
C. Glow-in-the-dark
cats
• Scientist used a
virus to insert DNA
from jellyfish
• The gene made the
cat produce a
fluorescent protein
in its fur.
2. Transgenic bacteria: gene inserted
into bacteria so they produce things
humans need.
• For example: insulin and clotting factors
in blood are now made by bacteria.
3. Transgenic plants: plants are given
genes so they meet human needs.
A. Transgenic corn: given a gene so corn
produces a natural pesticide.
Now they don’t have to be sprayed with
cancer causing pesticides.
• 25% of all corn is like this.
B. Venomous cabbage
• gene from a scorpion tails
inserted into cabbage.
• Cabbage now produces
that chemical.
• Why? Limit pesticide use
while still preventing
insects from damaging
crops.
• Corporations state the
toxin is modified so it isn’t
harmful to humans.
C. Banana vaccines
• virus is injected into a banana,
the virus DNA becomes part of
the plant.
• As the plant grows, it produces
the virus proteins — but not the
disease part of the virus.
• When people eat a bite, their
immune systems creates
antibodies to fight the disease —
just like a traditional vaccine
• Vaccines for hepatitis and
cholera
• A virus is often used to deliver DNA.
• In the movie “I Am Legend,” A healthy gene was
inserted into a virus.
• The virus invaded the cancer cells and inserts the
healthy gene to cure cancer.
• Worked at first but the virus mutated and became
deadly.
• This is being attempted in real life.
• Gene therapy: when disease causing
genes are cut out and good gene are
inserted.
• Restriction enzymes are used to cut out
bad genes.
• Viruses are used to insert good genes.
• Not approved for human use yet.
• Some possible side effects.
4. Gel electrophoresis: a
technique used to compare
DNA from two or more
organisms.
Why compare DNA:
1. Find your baby’s daddy
2. Who committed a crime.
3. How closely species are
related.
How is
electrophoresis
done?
A. The DNA is cut into
fragments with a
restriction enzyme.
B. The cut DNA is then
put into the wells of a
machine filled with
gel.
• The gel is spongy and
the DNA squeezes
through the pores.
C. The machine is plugged in and the
fragments get separated based on their size.
• The smaller fragments move further than the
large.
Separation of DNA based on
size of fragments.
• Electrophoresis
results
Final result of electrophoresis
• Electricity provides the energy
• Why does DNA move?
• DNA has a negative charge.
• When the machine is plugged it, its moves towards
the positive pole created by the electricity
electrophoresis
Your DNA is so unique its considered to be a
DNA fingerprint.
Gel electrophoresis will separate your DNA
differently from anyone else.
Nova: who done it
http://www.pbs.org/wgbh/nova/sheppard/analyze.html
http://www.teachersdomain.org/asset/tdc02_i
nt_creatednafp2/
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Genetic engineering creates organisms with
recombinant DNA.
Recombinant DNA: when DNA is combined
from at least two organisms.
Which techniques create recombinant DNA
1. Sexual reproduction: natural
2. selective breeding
3. Hybridization
4. Gene splicing
• Does cloning create organisms with
recombinant DNA?
• No, the DNA from one organism is
copied.
• DNA is not recombined.