CHAPTER 13
Standard 4.9
Genetic Engineering
11-8-2012
How can humans manipulate
DNA?
13-1
• Selective Breeding
Choosing the “best” traits for breeding
All products of selective breeding is artificial
selection
HORSES
Even Cows, Sheep, & Pigs
Hybridization
Crossing dissimilar individuals to bring
together the best traits of both
organisms
Produces hybrids
Golden Doodle Puggle
Designer breeds or
mutts?
Not to be confused with hybrid cars..
INBREEDING
Inbreeding = continued breeding of
similar individuals
(ex. pure breed dogs)
Has risks… increases breed’s susceptibility
to disease & deformities
Golden retrievers - epilepsy
Dalmations - hereditary deafness
Increasing Variation
Breeders can increase variation in a
population by inducing mutations
Mutation = any change in DNA
Mutations can
happen
randomly, as in
this Scottish
fold cat. Cat
enthusiasts
bred these cats
from a single
cat with a
mutation for the
ears.
Mutations produce new kinds of
bacteria
ex. oil-eating bacteria
Mutations produce new kinds of plants
Ex. day lilies, bananas, citrus fruits
Polyploid plants have multiple sets of
chromosomes.
13-2 DNA Technology
GENETIC ENGINEERING technology
that involves manipulating the DNA of
one organism in order to insert DNA of
another organism
= making changes in the DNA code of a
living organism
Different techniques are used…
• to extract DNA from cells
• to cut DNA into smaller pieces
• to identify the sequence of bases in
a DNA molecule
• to make unlimited copies of DNA
Bacterial Transformation
The changing of one strain of bacteria into another
strain
Plasmid: a circular piece
of DNA found in
bacteria
F+ bacterium contains a
plasmid
F- bacterium does not
contain a plasmid
Steps of Bacterial Transformation
1-Remove the plasmid from the bacterium.
Steps of Bacterial Transformation
2-Isolate the gene of interest.
A gene of interest is a piece of DNA that codes for
a protein we want more of
Steps of Bacterial Transformation
3-Open the plasmid by cutting it with a restriction
enzyme
This leaves “sticky ends”
Which need to be the complement of the sticky
ends left on the DNA fragment you want to
insert.
Sticky Ends
Sticky
Ends
The restriction enzyme EcoR1 cuts the DNA at the
sequence GAATTC, between the G and the A
Sticky Ends
Sticky Ends
Steps of Bacterial Transformation
4-Insert the gene of interest
Steps of Bacterial Transformation
5-Insert the plasmid with
recombinant DNA into a
new bacterium.
Recombinant DNA: DNA
produced by combining
DNA from different
organisms
Steps of Bacterial Transformation
6-The bacteria reproduces itself and the plasmid.
All descendants express the inserted gene
Bacterial Transformation
Other Types of Transformation
• Plants:
-Use bacteria that insert their plasmid into plant
cells
-removing cell walls sometimes allows plant cells
to take up foreign DNA on their own
Other Types of Transformation
• Animals:
-Many egg cells are large enough that DNA can
be directly injected
DNA SEQUENCE (Gel Electrophoresis)
- can be used to solve crimes or
determine paternity
- requires restriction enzyme to cut the
DNA , and electrophoresis to separate
it
Steps of Crime Scene Investigation or
Who the Baby DADDY????
a.) DNA extraction
b. Making Copies
Polymerase chain reaction (PCR)
used to make multiple copies of genes
c. cutting DNA – restriction enzymes
d.) separating & analyzing DNA
Scientist use gel electrophoresis =
Transgenic Organisms
Contains genes from other species
1.Microorganisms (bacteria)
2.Animals (mouse; medical uses)
3.Plants (agricultural uses)
*GM Crops
Gene causes these mice to glow in the dark. Normally,
the gene is found in jellyfish.
Cloning
• member of a population of genetically
identical cells produced from a single cell
• easy to clone single cell organisms
• multicellular organisms more difficult to
clone
• a twin is a natural clone
• 1997 Dolly the sheep cloned, 1st
mammal
Clones do exist naturally. These are identical twins.
How to Clone a Sheep
Cloning a Human
CC was the first cloned
cat (Rainbow is the
original). CC is short
for "Carbon
Copy". What is
interesting is the color
pattern for the clone is
different from the
original.
The reason is that the genes for
color randomly turn on or off for
the skin cells, creating random
coloration even on the cloned
cat.
How Can Cloning Be Useful?
1. Save endangered species by storing DNA and
cloning
2. Make multiple copies of a useful gene (insulin for
diabetics)
3. Clone spare parts, like organs or bone marrow
4. Create experimental groups for studying (animals)
5. Clone "special" animals,
pets or horses
Click and Clone
http://learn.genetics.utah.edu/content/tech/cl
oning/clickandclone/
Stem Cells
• Stem Cells unspecialized cells that can develop
into specialized cells
• Types of Stem Cells
– Embryonic
– Adult
– Pluripotent