Biotechnology
Biotechnology
 Biotechnology: broadly refers to the engineering of organisms
for useful purposes
 Often, biotechnology involves the creation of hybrid genes
and their introduction into organisms in which some or all of
the gene is not normally present.
Topics in Biotechnology
Genetically Modified Foods
Gene Cloning
Topics in Biotechnology
Gene Cloning
Molly the Sheep
Embryonic Stem Cells
Animal Cloning
 Why clone animals?
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To answer questions of basic biology
For pharmaceutical production
For herd improvement
To satisfy our desires (Ex. Pet cloning)
Biotechnology of Reproductive
Cloning
 Even under the best of
circumstances, the
current technology of
cloning is very inefficient.
 Cloning provides the most
direct demonstration that
all cells of an individual
share a common genetic
blueprint.
Carbon Copy – The First Cloned Pet
Recombinant DNA, Gene Cloning,
and Pharmaceutical Production
 These are mature and widely utilized biotechnologies.
 DNA can be cut at specific sequences using restriction enzymes.
 This creates DNA fragments useful for gene cloning.
Restriction Enzymes are Enzymes That Cut DNA
Only at Particular Sequences
The enzyme EcoRI cutting DNA at its recognition sequence
 Different restriction enzymes have different recognition sequences.
 This makes it possible to create a wide variety of different gene
fragments.
DNAs Cut by a Restriction Enzyme Can be Joined
Together in New Ways
These are recombinant DNAs and they often are made of DNAs from different
organisms.
Plasmids Used to Replicate
Recombinant DNA
 Plasmids are small circles of
DNA found in bacteria.
 Plasmids replicate
independently of the
bacterial chromosome.
 Pieces of foreign DNA can
be added within a plasmid
to create a recombinant
plasmid.
 Replication often produces
50-100 copies of a
recombinant plasmid in
each cell.
Harnessing the Power of Recombinant DNA
Technology – Human Insulin Production by
Bacteria
Human Insulin Production by Bacteria
and cut with a restriction enzyme
6) join the plasmid and human fragment
Human Insulin Production by Bacteria
Mix the recombinant plasmid with
bacteria.
Screening bacterial cells to learn which contain the human insulin gene is the
hard part.
Route to the Production by Bacteria of Human Insulin
One cell with the
recombinant
plasmid
This is the step when gene cloning takes place.
A fermentor used to grow
recombinant bacteria.
The single recombinant plasmid replicates within a cell.
Then the single cell with many recombinant plasmids produces trillions of
like cells with recombinant plasmid – and the human insulin gene.
Route to the Production by Bacteria of Human Insulin
The final steps are to collect the bacteria, break open the cells, and purify the
insulin protein expressed from the recombinant human insulin gene.
Route to the
Production by
Bacteria of
Human
Insulin
Cloning
animation
Pharming
Pharming is the production of pharmaceuticals in animals engineered to
contain a foreign, drug-producing gene.
These goats contain the human gene for a clotdissolving protein that is produced in their
milk.
The Stem Cell Concept
A stem cell is an undifferentiated,
dividing cell that gives rise to a
daughter cell like itself and a
daughter cell that becomes a
specialized cell type.
Stem Cells are Found in the Adult, but the Most Promising
Types of Stem Cells for Therapy are Embryonic Stem Cells
The Inner Cell Mass is the Source of Embryonic Stem Cells
The embryo is destroyed by separating it into individual cells for the collection of
ICM cells.
Some Thorny Ethical
Questions
Are these masses of cells a
human?
Is it ethical to harvest
embryonic stem cells from
the “extra” embryos created
during in vitro fertilization?
DNA, the Law, and Many Other Applications –
The Technology of DNA Fingerprinting
A DNA fingerprint used in a murder case.
The defendant stated that the blood on his clothing was his.
What are we looking at? How was it produced?
DNA Fingerprinting Basics
Different individuals carry different alleles.
Most alleles useful for DNA fingerprinting differ on the basis of the
number of repetitive DNA sequences they contain.
DNA Fingerprinting Basics
If DNA is cut with a restriction enzyme
that recognizes sites on either side of
the region that varies, DNA fragments
of different sizes will be produced.
A DNA fingerprint is made by analyzing
the sizes of DNA fragments produced
from a number of different sites in the
genome that vary in length.
The more common the length variation
at a particular site and the greater the
number the sites analyzed, the more
informative the fingerprint.
A Site With Three Alleles Useful for DNA Fingerprinting
DNA fragments of different size will be produced by a restriction
enzyme that cuts at the points shown by the arrows.
The DNA Fragments Are Separated on the Basis of Size
The technique is gel electrophoresis.
The pattern of DNA bands is compared between each sample loaded
on the gel.
Possible Patterns for a Single “Gene” With Three Alleles
In a standard
DNA
fingerprint,
about a dozen
sites are
analyzed, with
each site
having many
possible
alleles.
A DNA Fingerprint
When many genes are
analyzed, each with
many different alleles,
the chance that two
patterns match by
coincidence is vanishingly
small.
DNA and the Law
Some applications of DNA
fingerprinting in the justice system.
SLT 3/8/05
Genetically Modified Foods
Many of our crops in the US are genetically modified.
Should they be?
GM Crops are Here Today
Source: Pew Initiative on Food and Biotechnology, August 2004.
Methods for Plant Genetic Engineering are WellDeveloped and Similar to Those for Animals
Golden Rice is Modified to be Provide a Dietary Source
of Vitamin A
Golden rice
(yellow) with
standard rice
(white).
Worldwide, 7% of children suffer vitamin A deficiency, many of them living in
regions in which rice is a staple of the diet.
Genetically Modified Crops
Genetically Modified Cotton
(contains a bacterial gene for
pest resistance)
Standard Cotton
Current Concerns by Scientists Focus on
Environmental, Not Health, Effects of GM Crops
The jury’s still out on the magnitude of GM crop’s ecological impact, but the
question is debated seriously.
Current
Concerns by
Scientists Focus
on
Environmental,
Not Health,
Effects of GM
Crops