Genetic engineering

Genetic Engineering and Cloning

News Flash

Quiz over Mutations and DNA
Necklace Lab on Wed / Thurs
1/18 & 1/19


Bring Textbook to class
on Block Day!

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!

Slide # 2

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!

Hybridization

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

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.
Golden rice
contains the gene
from daffodils that
produces vitamin A.



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?

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 # 5

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 # 6


How Animals are Cloned

Dolly: First cloned mammal

It took scientists 276 attempts to produce a cloned embryo

Dr. Ian Wilmut cloned Dolly

Slide # 7

Born July 5, 1996

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

C

D

Slide # 8

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

Slide # 9