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Gene Technology
Molecular genetics- scientist study DNA
molecules and make changes in the DNA.
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Genetic Engineering- changes an organisms
DNA
DNA extraction: separates DNA from the rest
of the cell.
Restriction enzymes cut DNA into smaller
fragments.
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They only fit one certain nucleotide sequence, so the
DNA molecules are cut precisely where the scientists
need them to be cut.
The ends of DNA are known as sticky ends.
The cut DNA is placed in little wells in the
electrophoresis gel.
The gel is placed into a solution, then an electric field
runs through the gel.
The DNA pieces move through the gel at different
rates according to size and electrical charge.
The shortest pieces will move the farthest from the
well.
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Gel electrophoresis- separates the cut DNA into fragments
by using the restriction enzymes, then places the
fragments in wells.
An electrical field runs through the gel, and the DNA
separates by size and electrical charge.
Shortest pieces move to the farthest.
Gel electrophoresis is MOST important in DNA
fingerprinting.
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Everyone’s DNA is different.
The fragments from gel electrophoresis are treated with
radioactive probes, and the end result is a pattern of bands
that are unique to each person.
Used in criminal cases
Used to show if people are related to each.
Recombinant DNA is made by taking short pieces of DNA
from one organism and joining it to the DNA of a
completely different organism.
Once the DNA is made, it can be placed back into a living
cell in a process called transformation.
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Useful in medicine
Ex. Insulin is a hormone needed for diabetes that can be made
using bacteria by inserting recombinant DNA into the bacteria.
The bacteria reproduces quickly, so many copies of the insulin
gene are mass produced very quickly.
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
Cloning Vectors:
Bacterial cells reproduce quickly.
They contain small circular pieces of DNA called plasmids.
The plasmid has the DNA piece cut by restriction enzymes
that are placed in it to then make copies of the
gene. (Ex. insulin gene)
Scientists are working to “replace” defective genes with
normal genes. This could one day replace genes
that code for harmful genetic disorders like
Huntington’s Disease, sickle cell anemia, etc…
**(Gene Therapy – replacing a mutated gene with
a normal gene)
Bacteria used in genetic
engineering
Transgenic organisms (often animals)—Organisms
that contain genes from different organisms.
Transgenic cows have extra copies of growth
hormone genes.
These animals will grow faster and have meat
that is less fatty than beef from regular cows.
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The cows can be grown quicker, so farmers make more
money, and the shoppers pay less money.
Some people are concerned that transgenic plants
could pollinate wild plants and produce plants could
not be controlled with weed killers, or worse, end up
being harmful to beneficial pests.
People wonder if the extra growth hormone in
transgenic beef could affect the humans who consume
it or if antibiotic-resistant genes sometimes used in
transformation could spread into the environment and
cause bacteria to be antibiotic- resistant.
Often termed genetic pollution or frankenfoods
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??
Injaz, camel
SNUPPY,
afghan
hound (2005)
*Most recently cloned
3/8/2009
Dolly,
sheep
(1996)
Chapter 6
Kendall/Hunt Publishing Company
15
Cloning
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Chapter 6
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???
Kendall/Hunt Publishing Company
16
The Human Genome Project:
The effort to map the sequence of all
the human genes.
Completed in the year 2002. Created
maps to show the locations of all the
genes on every chromosome.
This diagram shows what a sample gel
with DNA bands would look like.
Do the remaining bands match the father?
Yes
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