Transcript Genetic engineering

Genetic Engineering and Cloning
Slide # 2
About Genetic Engineering
1.Genetic engineering:
changing an organism’s
DNA to make it more
beneficial to humans
a.Genetic engineering has
been going on a very
long time in the form of
selective breeding!
b.Changing a cell’s genome
by inserting or removing
DNA is very new
technology!
All of the different types of
chili peppers are are result
of selective breeding – a
form of genetic engineering!
Selective Breeding: Creating Plants and
Animals for Our Benefit
1.Selective Breeding: Selecting
individuals with the desired
traits to produce offspring for
the next generation
a.Used since the beginning of
agriculture to produce
superior plant species
b.Used to produce breeds of
domestic animals – dogs,
horses, cats, sheep, cattle
2. Also called artificial selection
All of the different plants
produced from wild mustard
by selective breeding!
1.Hybridization: crossing 2
dissimilar, but related
organisms
a.Offspring called hybrids
2. Advantages:
a.Usually
stronger/hardier than
parents – known as
hybrid vigor
3. Disadvantages:
a.May promote the loss
of native species
Hybridization
1. African catfish (left) grows
faster than Thai catfish.
2. Thai catfish (middle) has
better tasting flesh than
African catfish.
3. Hybrid (right) grows fast &
has good tasting flesh.
Genetic Engineering: Recombinant DNA
1. Recombinant DNA: made from pieces of DNA
from separate organisms; the pieces stick together
a. DNA from different organisms are “recombined”
2. How recombinant DNA is made:
Transgenic Organisms: Plants
1. Transgenic organisms:
any organism that has
genes from a different
organism inserted into
its DNA.
2. Genomes can be
produced that could
never be produced by
nature
a. EX: Rice plants and
daffodils usually do
not cross pollinate
each other in nature
The rice on the right is called golden
rice. Its genome contains the gene for
producing vitamin A from daffodils.
This rice is healthier for people who do
not get enough vitamin A in their diets.
DNA Fingerprinting:
1. DNA fingerprinting: tool used by
forensics scientists to identify a person
using DNA.
2. How it Works:
• A sample of the person’s DNA is taken
from blood, semen, bone, or hair.
• DNA fragments are placed into a gel &
connected to an electric current
• DNA moves through gel; shortest
lengths move fastest & longest lengths
move slowest.
• Banding pattern is produced
• The banding is unique for each person
– thus called DNA fingerprinting
Was any of the
victims blood on the
defendants clothing?
Slide # 5
Reading DNA Fingerprints
1. DNA fingerprinting is used as
evidence in court cases
2. DNA fingerprints are used to
support other facts presented
to the court
3. A photograph is taken of the
bands in the gel & then the
bands are compared to the
victim’s
Which dog was probably
the culprit (dog that bit
the person)?
Slide # 6
How Cloning Occurs in Nature
1. Clone: an organism that is
genetically identical to another
organism
a. All of the genes are the same
(identical)
2. Examples of cloning that occurs in
nature
a. Self-pollination
b. Reproduction in bacteria
c. “budding” in sponges
d. Regeneration of rays in sea stars
Slide # 7
How Animals are Cloned
Born July 5, 1996
Dolly: First cloned mammal
It took scientists 276 attempts to produce a cloned embryo
Dr. Ian Wilmut cloned Dolly
Slide # 8
How was Dolly Cloned?
1. Process is called somatic cell
nuclear transfer
a. Nucleus from an adult cell
(A) is transferred to an
unfertilized egg that has
had its nucleus removed
(B)
b. The “fertilized egg” cell is
stimulated to divide using
electric shock
c. The embryo is implanted
into a surrogate mother (C)
2. The “baby” (D) is a clone of
the animal that the somatic
cell (A) was taken from
A
B
D
C
Slide # 9
Uses and Risks of Cloning Animals
Uses:
1. Medical purposes: producing cloned
animal models, stem cell research,
and for producing medicines
2. Saving Endangered Species
Risks:
1. Somatic cell nuclear transfer is
inefficient; only 0.1 to 3 % success
rate (Dolly was attempt # 277!)
2. Cloned animals are larger at birth
and have larger internal organs; can
lead to breathing and blood flow
problems
Cloned in 2003 at
Texas A & M