Genetic Engineering
13-1 Changing the Living World
Selective Breeding
Hybridization
Inbreeding
Increasing Variation
13-2 Manipulating DNA
The Tools of Molecular Biology
DNA Extraction
Cutting DNA
Separating DNA
Using the DNA Sequence
Reading the Sequence
Cutting and Pasting
Making Copies
13-3 Cell Transformation
Transforming Bacteria
Transforming Plant Cells
Transforming Animal Cells
13-4 Applications of Genetic Engineering
Transgenic Organisms
Transgenic Microorganisms
Transgenic Animals
Transgenic Plants
Cloning
Changing the Living World
• Genetic engineering is
the alteration of genetic
code by artificial means,
and is therefore different
from traditional selective
breeding. Only allowing
desired characteristics to
reproduce.
• Scorpion poison DNA is
located and inserted into
cabbage DNA. Cabbage
kills caterpillars
(insecticide).
Selective breeding
• Hybridization - the act
or process of mating
organisms of different
varieties or species to
create a hybrid.
Selective Breeding
Hybridization cont.
Insecticide resistant crops
Herbicide resistant crops
Vitamin enriched crops
• Maize streak virus symptoms
in a commercial maize field in
Klerksdorp, NorthWest South
Africa, showing chlorotic
streaking and deformed cob
development. This farm grew
USA commercial hybrids and
experienced almost total yield
losses.
Selective Breeding
• Inbreeding-is the
continued breeding of
individuals with similar
characteristics.
Pros- maintains
characteristics of the
breed
Cons- genetic defects
more common
Increasing Variation
• In nature there is a lot
of genetic variation
found in wild natural
populations.
• Breeders can increase
variation by inducing
mutations.
• Ex. Belgium Blue –
myostatin muscle
mutation
Increasing Variations with Mutations
• Oil eating bacteria
strains created using
mutations
Increasing Variation…. with mutations
• Plants have success by
introducing more
chromosomes (mutation).
• Polyploidy is caused by
drugs that double or
triple the amount of
chromosomes. The effect
causes larger and
stronger plants.
• Citrus fruits, bananas
• Not successful with
animals
Manipulating DNA
• Scientists use their
knowledge of the
structure of DNA and its
chemical properties to
study and change DNA
molecules. Different
techniques are used to
extract DNA from Cells.
Manipulating DNA
Different techniques are
used to :
• extract DNA from cells
• cut DNA into smaller
pieces
• identify the sequence
of bases in a DNA
molecule
• make unlimited copies
of DNA.
The Tools of Molecular Biology
• Genetic Engineering –
making changes in the
DNA code
• DNA Extraction – The
cells are opened and
the DNA is separated
from the other cell
parts.
The Tools of Molecular Biology
Cutting DNA
• DNA strands are too
long to work with so
scientists use restriction
enzymes to cut DNA
into fragments, at
precise points, on the
DNA strand.
• Fits like a “lock and key”
when the DNA is
opened.
The Tools of Molecular Biology
Separating DNA
• How DNA is separated
and analyzed
• Gel electrophoresisused to compare
genomes or gene
composition of different
organisms or individuals
Using the DNA Sequence
• Once DNA is in a
manageable form, it
sequence can be read,
studied, and even
changed. Knowing the
DNA sequence allows
researchers to study
specific genes, to
compare them, and to try
to discover the functions
of different genes and
gene combinations.
Using the DNA Sequence
• A chemical dye is added
as a marker on bases to
help read the DNA
sequence before
electrophoresis is
started.
Using the DNA Sequence
Cutting and Pasting
• “Synthetic” sequences
can be joined to “natural”
sequences using enzymes
that splice DNA together.
It’s like taking a gene from
one organism and
implanting it in another
organism.
• Recombinant DNA is
produced by combining
DNA from different
sources.
Using the DNA Sequence
Making Copies
• Scientists need many
copies of a particular
gene to study
• Polymerase Chain
Reaction (PCR) is a
technique used to make
DNA copies.
Cell Transformation
• During transformation,
a cell takes in DNA from
outside the cell. This
external DNA becomes
a component of the
cell’s DNA.
-ex. Griffith’s
experiment, in 1928,
proved bacteria could
transform DNA
Griffith’s Experiment
Transforming Bacteria
• Bacteria can be transformed
using recombinant DNA
• Foreign DNA is joined to the
bacteria’s DNA in the
Plasmid.
• Plasmid’s contain DNA in
the bacteria
-contains DNA sequences
that promotes plasmid
replication
-Plasmid’s contain genetic
markers making it easy to
identify transformed
bacteria.
Transforming Plant Cells
• Many plants are
transformed by using
bacteria that insert their
DNA into a plant cell to
produce tumors
1) Scientists turn off the
gene for tumors and
insert recombinant DNA
into the plasmid.
2) Then the recombinant
plasmid can be used to
infect plant cells
Transforming Plant Cells cont…
• When plant cell walls are
removed, plant cells in
culture will sometimes take
up DNA on their own.
-DNA can also be injected
into some plant cells.
• Tobacco plant cells
transformed with
reprogrammed virus. Virus
makes chromophores to get
energy from the sun to be
used in solar panels.
Transforming Animal Cells
• Animal cells can be
transformed in some of the
same ways as plant cells
• Egg cells can be injected
w/foreign DNA into the
nucleus
• Foreign DNA contains
markers for identification by
scientists
• Genes can be replaced with
new genes
• Great for figuring out the
specific functions of genes
Applications of Genetic Engineering
• Genetic engineering makes
it possible to transfer DNA
sequences, including whole
genes, from one organism
to another.
-including plants to animals
-Enzyme luciferase, gene
fireflys glow, combined with
tobacco plant
• Proved that the basic
mechanisms of gene
expression are shared by
plants and animals.
Transgenic Organisms
• DNA allows us to construct
organisms that are
transgenic.
• Transgenic means that
organisms contain genes
from other species.
• Transformed cells can
create whole new
organisms
ex. Glow in dark cats,
transgenic salmon
compared to regular salmon
after one yr.
Transgenic Microorganisms
• Transgenic bacteria used
to create important
substances useful in
health and industry
-reproduce rapidly
-easy to grow
-cheap
ex. Insulin, growth
hormone, clotting factor,
Pic- chickens that can’t
pass the bird flu
Transgenic Animals
• Pic – turned off myostatin
gene more muscle with-out
more food
• Used to study genes and to
improve the food supply
• Mice given human genes to
mimic our immune systems
to study diseases
• Livestock given extra growth
hormone to grow faster
• Chickens bacterial resistant
to bacteria that cause food
poisoning
• Sheep and pigs make
human milk (proteins)
Transgenic Plants
• Important part of the food
supply
• Insecticide and herbicide
resistant
• Food with more vitamins
(Vit.A rice)
• May soon produce
-human antibodies that
can be used to fight
disease
-Plastics from plants
(maybe)?
- Food resistant to rot and
spoilage
Cloning
• A clone is a member of a
population of genetically
identical cells produced
from a single cell.
• Bacteria are easy to clone
• Multi-cellular organisms
are more difficult to clone
• Help save endangered
species
• 1997 William Wilmut
cloned Dolly