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Genetic Engineering
IV. Genetic Engineering
A. Selective Breeding- allowing only those
animals with desired traits to produce the next
generation. (domestic animals: horses, cats, farm
animals, crop plants)
1. Hybridization- crossing dissimilar
individuals to bring together the best of both
organisms. (e.g. disease resistance and foodproducing capacity)
Hereford, bred for
meat production
2. Inbreeding- continued breeding of
individuals with similar characteristics. Can
create serious problems (bringing together 2
recessive alleles)
Albinism present in Hopi
Indians. Only albino
children are produced by
albino parents. Two
phenotypically normal
individuals produce
albino and non-albino
children. Frequency in
US while population = 1
in 37,000. Hopi and
Navajo Indians = 1 in
200
Inbreeding in small ponds of
gardens and parks as well as
larger rural ponds due to
increasingly limited
environments, criss-crossed with
roads and other barriers.
Individuals from less diverse
urban populations had a lower
survival rate and showed more
abnormalities during
development, suggesting that
inbreeding had exposed harmful
mutations which reduced fitness.
B. Increasing Variation
1. Can increase variation by inducing
mutations (using radiation or chemicals)
2. Many mutations are harmful. A few can be
beneficial
3. Inducing mutations can increase genetic
variation.
These “oil-eating” bacteria
were produced by treating
the bacteria with chemicals
and radiation, thus inducing
a mutation. Hundreds of
other useful bacterial
strains have been produced
this way.
C. Manipulating DNA
1. Scientist use knowledge of DNA to change
DNA molecules
2. Techniques used to extract DNA, cut into
smaller pieces and identify base sequences,
make unlimited copies of DNA
3. Genetic engineering- making changes to
DNA code and putting back into cell (by
injection into cell, by bacteria, viruses)
Steps:
• A. DNA extraction- cells are opened and
DNA is separated from the other cell parts.
• B. Cutting DNA- cut into small fragment
by restriction enzymes (cut DNA at a
specific sequence of nucleotides).
• C. Separating DNA – method is gel
electrophoresis
• Steps:
• 1. A mixture of DNA fragments is place at one
end of a porous gel
• 2. Electricity is applied to the gel.
• 3. DNA molecules, which are negatively charged,
move toward the positive end of the gel
• 4. Smaller DNA fragments move faster and
farther.
• 5. Based on size the DNA fragments make a
pattern of bands on the gel that can be compared
with other samples.
Figure 13-6 Gel Electrophoresis
Section 13-2
DNA plus
restriction
enzyme
Power
source
Longer
fragments
Shorter
fragments
Mixture of
DNA
fragments
Go to
Section:
Gel
II. Applications of Genetic Engineering
A. Transgenic organisms- bacteria, plants, and
animals that contains genes from other organisms
1. Transgenic microorganismsbacteria used to produce many
important substances for health
and industry (e.g. transformed
bacteria now make insulin, growth
hormone, clotting factor cheaply
and in great abundance)
Transgenic tobacco plant- glows in
the dark. Produced by transferring a
gene from a firefly into a tobacco
plant
2. Transgenic Animals- faster growing animals,
resistance to disease, etc.
A transgenic pig with higher levels of growth
hormone produced the meatier pork chop.
3. Transgenic Plants- important part of our food
supply. (52% of soybeans and 25% of corn are
transgenic) resistant to disease, produce their
own insecticide, resist weed-killing chemicals,
increase vitamin content
Transgenic tomato plants containing genes for viral resistance and
healthier than those without the resistant genes (right)
Frost-damaged
citrus trees. Plans
for the release of
genetically
engineered
bacteria hope to
reduce frost
damage
B. Cloning- a member of a population of
genetically identical cells produced from a single
cell
The adult sheep is Dolly,
the first mammal cloned
from an adult cell. The
lamb is Dolly’s offspring,
called Bonnie.
• Steps:
1. Donor cell taken
2. Nucleus of egg cell is removed
3. Donor cell is fused with egg cell
4. Fused cell begins to divide and become an
embryo
5. Embryo is placed in a foster mother’s uterus
6. Embryo develops normally and is born
1. May find wide use in medical and scientific
research
2. Raises serious ethical issues
• A. Cloning Vector- a carrier that is used to
clone a gene and transfer it form one
organisms to another.
• B. Donor gene- specific gene from another
organism spliced into a plasmid, that
replicates as the bacteria divide
– 1. A plasmid is a circular DNA molecule found
in bacteria.
C. Gene Clone- exact copy of a gene
• D. Steps in getting DNA for cloning
1. Cleaving DNA- cutting DNA into fragments using
restriction enzymes
a. Restriction enzymes recognize and bind
to specific short sequences of DNA and
cut it at a specific site within the
sequence.
b. It is not cut straight and creates single
stranded DNA pieces with “sticky ends”
c. Sticky ends of DNA pair back up and
heal the break or pair with any other
fragment cut by the same enzyme.
• 2. Producing Recombinant DNA- it is inserted
into a plasmid and allowed to infect the target
cells (vector)
• 3. Cloning target cells- target cells are allowed
to grow and reproduce
• 4. Screening target cells- target cells that have
received the particular gene are isolated
Restriction Enzymes
Recognition
sequences
Section 13-2
DNA
sequence
Restriction
enzyme EcoRI
cuts the DNA into
fragments.
Go to
Section:
Sticky end
III. Plant Cloning
• A. Ti Plasmid- used as a vector to carry
genes into plants.
– 1. caused by large tumors in plants
– 2. tumor gene removed and space filled by
desired gene
– 3. Cannot be used in plants that produce cereal
grains
Figure 13-9 Making
Recombinant DNA
Recombina
nt DNA
Gene for
human
growth
hormone Sticky
ends
Human
Cell
Bacterial
Cell
Bacterial
chromoso
me
Plasmid
Go to
Section:
DNA
recombinati
on
Gene for human
growth hormone
DNA
insertio
n
Bacterial cell for
containing gene
for human growth
hormone
IV. Human Genome Project
A. Was stated in the late 1980’s, as an
international effort to determine the
nucleotide sequence and location of every
gene on each chromosome.
B. Completed in April 2003.
Chapter 13
Genetic Engineering
Which of the following have been produced by
selective breeding?
a.
horse breeds
b.
cat breeds
c.
dog breeds
d.
all of the above
Which of the following have been produced by
selective breeding?
a.
horse breeds
b.
cat breeds
c.
dog breeds
d.
all of the above
Selective breeding produces
a.
more offspring.
b.
fewer offspring.
c.
desired traits in offspring.
d.
transgenic organisms.
Selective breeding produces
a.
more offspring.
b.
fewer offspring.
c.
desired traits in offspring.
d.
transgenic organisms.
Which of the following is most likely to bring
together two recessive alleles for a genetic
defect?
a.
inbreeding
b.
hybridization
c.
genetic engineering
d.
transformation
Which of the following is most likely to bring
together two recessive alleles for a genetic
defect?
a.
inbreeding
b.
hybridization
c.
genetic engineering
d.
transformation
The crossing of buffalo and cattle to produce
beefalo is an example of
a.
inbreeding.
b.
hybridization.
c.
genetic engineering.
d.
transformation.
The crossing of buffalo and cattle to produce
beefalo is an example of
a.
inbreeding.
b.
hybridization.
c.
genetic engineering.
d.
transformation.
Scientists produced oil-eating bacteria by
a.
making bacteria polyploid.
b.
inbreeding bacteria.
c.
inducing mutations in bacteria.
d.
hybridizing bacteria.
Scientists produced oil-eating bacteria by
a.
making bacteria polyploid.
b.
inbreeding bacteria.
c.
inducing mutations in bacteria.
d.
hybridizing bacteria.
What is the ultimate source of genetic
variability?
a.
inbreeding
b.
radiation
c.
hybridization
d.
mutations
What is the ultimate source of genetic
variability?
a.
inbreeding
b.
radiation
c.
hybridization
d.
mutations
Breeders induce mutations in organisms to
a.
increase diversity in populations.
b.
make organisms more alike.
c.
avoid selective breeding.
d.
produce organisms with undesirable
characteristics.
Breeders induce mutations in organisms to
a.
increase diversity in populations.
b.
make organisms more alike.
c.
avoid selective breeding.
d.
produce organisms with undesirable
characteristics.
One function of gel electrophoresis is to
a.
separate DNA fragments.
b.
cut DNA.
c.
recombine DNA.
d.
extract DNA.
One function of gel electrophoresis is to
a.
separate DNA fragments.
b.
cut DNA.
c.
recombine DNA.
d.
extract DNA.
The process of making changes in the DNA
code of living organisms is called
a.
selective breeding.
b.
genetic engineering.
c.
inbreeding.
d.
hybridization.
The process of making changes in the DNA
code of living organisms is called
a.
selective breeding.
b.
genetic engineering.
c.
inbreeding.
d.
hybridization.
Genetic engineering involves
a.
reading a DNA sequence.
b.
editing a DNA sequence.
c.
reinserting DNA into living organisms.
d.
all of the above
Genetic engineering involves
a.
reading a DNA sequence.
b.
editing a DNA sequence.
c.
reinserting DNA into living organisms.
d.
all of the above
What kind of techniques do scientists use to
make transgenic organisms?
a.
hybridization
b.
inbreeding
c.
inducing of mutations
d.
genetic engineering
What kind of techniques do scientists use to
make transgenic organisms?
a.
hybridization
b.
inbreeding
c.
inducing of mutations
d.
genetic engineering
What is an advantage of using transgenic bacteria to
produce human proteins?
a.
The human proteins produced by transgenic
bacteria work better than those produced by humans.
b.
Transgenic bacteria can produce human proteins
in large amounts.
c.
The human proteins produced by transgenic
bacteria last longer than those produced by humans.
d.
Transgenic bacteria can produce human proteins
used to make plastics.
What is an advantage of using transgenic bacteria to
produce human proteins?
a.
The human proteins produced by transgenic
bacteria work better than those produced by humans.
b.
Transgenic bacteria can produce human
proteins in large amounts.
c.
The human proteins produced by transgenic
bacteria last longer than those produced by humans.
d.
Transgenic bacteria can produce human proteins
used to make plastics.
What has been an advantage of producing
transgenic plants?
a.
increasing the food supply
b.
using more pesticides
c.
producing clones
d.
studying human genes
What has been an advantage of producing
transgenic plants?
a.
increasing the food supply
b.
using more pesticides
c.
producing clones
d.
studying human genes
The Scottish scientist Ian Wilmut cloned a
a.
bacterium.
b.
sheep.
c.
plant.
d.
cow.
The Scottish scientist Ian Wilmut cloned a
a.
bacterium.
b.
sheep.
c.
plant.
d.
cow.
Why is Dolly a clone?
a.
The source of her DNA was a single
body cell.
b.
The DNA molecules in all her cells are
identical.
c.
She was produced using the DNA from
an adult’s egg cell.
d.
She is genetically identical to her
offspring.
Why is Dolly a clone?
a.
The source of her DNA was a single
body cell.
b.
The DNA molecules in all her cells are
identical.
c.
She was produced using the DNA from
an adult’s egg cell.
d.
She is genetically identical to her
offspring.
Humans use selective breeding to pass
desired _________________________ on to
the next generation of organisms.
Traits
Characteristics
____________________ is the technique of
selective breeding that has led to deformities in
certain dog breeds.
Inbreeding
To produce a fruit that has some
characteristics of an orange and some of a
grapefruit, you would use the selective
breeding technique of
_________________________.
hybridization
Scientists use radiation and chemicals to
induce ____________________.
mutations
DNA samples taken from Dolly and the sheep
that donated the body cell would show
____________________ patterns of bands on
an electrophoresis gel.
Identical
The same