Transcript Genetic Engineering

Ch 9
Gene maps and the
Human Genome Project
Manipulating DNA
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Scientists use enzymes that act as
molecular “scissors” to splice DNA.
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These enzymes (restriction enzymes)
come from bacteria cells!
Bacteria use these enzymes to cut DNA of
viruses that invade them.
Restriction Enzymes
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Enzymes that cut DNA molecules at
specific nucleotide sequences.
What can we use them for?
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If we can cut out different fragments of DNA
carrying specific genes we can also insert
them into new DNA strands and modify an
organism’s DNA!
http://www.youtube.com/watch?v=-sI5vycD2g
http://www.dnalc.org/view/15476Mechanism-of-Recombination-3Danimation-with-with-basic-narration.html
Gel Electrophoresis
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DNA fragments can also be separated and
sorted according to their sizes using Gel
electrophoresis.
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A electrical current is used
DNA is loaded into a gel which has a positively
charged electrode on one end and negatively
charged electrode on the other.
DNA fragments(neg charged) move towards the
positive side. Smaller pieces move farther down
(move more quickly)
A Restriction Map results
http://www.youtube.com/watch?v=PSwlCk_Z02c
Restriction Maps
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Helpful in Genetic engineering and the
study of mutations
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DNA strands with mutations will result in
maps with different results!
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DNA Fingerprinting
1. no human is genetically identical to
another unless they are identical twins
2. If DNA is found at a crime scene it can
be compared to a sample taken from the
suspect.
3. the bands on pieces of DNA can be
compared to each other to find a match
Wrongful convictions overturned
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http://www.pbs.org/wgbh/nova/sheppard
/cleared.html
Gene Maps:
Show the locations on a chromosome of
individual genes
Drosophila chromosome map
Example of
gene
mapping…
(not the real Y
chromosome!!)
D. Gene mapping led to the Human
Genome Project
E. The entire human genome was finished
being mapped in June 2000 (there are
more than 3 billion bases)
II.
A. Genetic testing makes it possible to
determine what disorders parents might
pass on to their children
B. Gene Therapy
1. replacing an absent or faulty gene with
a normal, working one
http://www.youtube.com/watch?v=ujf72mjy0
Bg
2. high risk and experimental
3. August 2002 successful treatment by
gene therapy for X-linked
immunodeficiency disease also known
as "bubble baby syndrome."
http://www.youtube.com/watch?v=bLI1Gfb
0ynw
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http://www.youtube.com/watch?v=LVKq
V7a31Rs
By number, not mass!
Dolly the cloned sheep
Genetic Engineering
a glowing transgenic tobacco plant
bearing the luciferase gene of
fireflys
I. Genetic Modification
A.
B.
C.
Altering an organism’s DNA by removing
genes or adding new ones
Involves the use of Recombinant DNA (DNA
that contains genes from more than one
organism)
Can be added from the same species or
different ones
ex. Scientists are trying to insert a gene
from cold water flounder into tomato plants to
help them resist frost.
True or False
A new finding could lead to Genetically
Modified onions that don’t make us cry as
we chop them. Researchers in Japan
have identified the enzyme that releases a
tear-duct-tickling chemical when an onion
is cut. The gene that controls the
production of this enzyme was isolated
and can now be turned off. A GM onion
lacking the enzyme would taste the same
but not irritate your eyes.
TRUE!!
True or False
A new genetically modified rice may save
over 250 million people around the world
from permanent blindness and 1-3 million
from death caused by a vitamin A deficiency.
A rich source of vitamin A is a chemical
called beta-carotene, found in some plants
like carrots. The GM rice, called “golden rice”
because of its color, contains a gene from a
daffodil that is inserted into the rice providing
beta carotene that is converted into vitamin A
in the body.
TRUE!!
True or False
Scientists at the American Association of
Genetic Modification have identified the gene
that makes blueberries blue and have put it
into a strawberry. The genetically modified
strawberries taste exactly the same, but are
blue in color. It is hoped that this will make
the fruit more appealing to children. The GM
blue strawberries have been tested on
children (who seem to enjoy them) during the
initial trials and supermarkets are already
interested.
FALSE!!
YOU CAN NOT USE HUMANS IN THE FIRST TRIALS!!
II. Selective Breeding/
Artificial selection
A. Only organisms with desired
characteristics are allowed to produce
another generation
Ex. Disease resistant potatoes = end to
potato blight and famine
Cows that produce the most milk = more $
III. Hybridization
A. Crossing desired traits in two different
organisms to create a new organism
with both traits.
B. Offspring are usually sterile
Examples: a plant that produces large
amounts of fruit with a plant that resists
disease
A Jug: pug/jack russell
a labradoodle: labrador/poodle
Mule: horse/donkey
IV. Inbreeding
A. Maintaining desired characteristics by
breeding with organisms possessing the
trait. “Pure bred dogs”
B. Risks:
genetic defects due to recessive alleles
german shepherds = bad hip joints
VI. Genetic Engineering
A. Making changes in DNA of a living
organism
B. Recombinant DNA is the result
C. Transgenic – organisms that have
genes from OTHER species
ex.- Glow in the dark tobacco
plants
-bacteria that produce human
insulin
Ruppy the
first
transgenic
dog
Red pigment
taken from sea
anemones
VII. Cloning
A. An organism that is genetically
identical to the donor.
Dolly the clone and her
baby Bonnie
One bacteria produces a
colony of clones
https://www.youtube.com/watch?v=YoEWYJHf0kU
B. The nucleus is taken out of a donor cell
and put into the target egg cell who’s
nucleus was removed. A zap of electricity
is used to fuse it with the cytoplasm
C. Egg cell is implanted into a surrogate
mother and a clone develops (p. 332)
D. Cloning stem cells creates donor organs,
save endangered species
E. No genetic diversity, success rate poor
(277 tries to make Dolly), expensive,
health problems (Dolly had arthritis and
organ failure at an early age)
https://www.youtube.com/watch?v=W4vOPaonZng
Should cloning be allowed?
http://learn.genetics.utah.edu/
content/cloning/clickandclone/
Do Now
 What
is one risk and one benefit
of cloning?
GMOs
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http://www.youtube.com/watch?v=jAP6Z
tfP9ZQ