Transcript Recombinant DNA - University of Central Oklahoma

If your eyes follow the movement of the rotating pink dot, you will only see one color, pink. If you
stare at the black + in the center, the moving dot turns to green. Now, concentrate on the black + in
the center of the picture. After a short period of time, all the pink dots will slowly disappear, and
you will only see a green dot rotating if you're lucky! It's amazing how our brain works. There
really is no green dot, and the pink ones really don't disappear. This should be proof enough, we
don't always see what we think we see.
Recombinant DNA
Microbiology 2314
California 2003
• In Sacramento, a group of
scientists have genetically
altered fish. Basically they
took ordinary zebra fish,
added genetic jellyfish stuff,
and made pet fish that glow
in the dark, when placed
under a blacklight. They hit
the shelves in 2004 to be
sold as pets.
• They will be on sale, just about everywhere except
California (which bans lab-engineered species.)
So…We can genetically engineer
all the animals we want, just can’t
sell em.
What is Genetic Engineering?
• Genetic engineering (GE) is the transfer of genes
from one organism to another through means that
do not occur in nature, but through human
intervention. This involves isolating and then
moving genes within and without different species
by recombinant DNA techniques and other
manipulation of the genetic construct outside the
traditional practices such as sexual and asexual
breeding, hybridization, fermentation, in-vitro
fertilization and tissue culture.
Introduction
• Biotechnology
- The use of microorganism cells or cell
components to make a new product.
• Idea More than 60 Years Old
• Delay Due to Technology
1. Cut
2. Combine
3. Reinsert
Advent of Recombinant DNA
• Closely Related Organisms Can Exchange
Genes
• Labs Can Facilitate Transfer Between
Unrelated Species
• DNA Transfers Genes
Tools and Techniques
•
•
•
•
Restriction Enzyme Makes Cuts
Cuts at Specific DNA Sequences
Accurate
75 Known Restriction Enzymes
Sticky Ends/Blunt Ends
DNA Ligase
• Vectors
- Called Chimeras
• Shuttle Vectors
- Plasmids that can exist in several
different species.
• Transformation
- Process by which a new gene is
inserted into a cell
Process
• Isolate the Source and Vector DNA
• Use Restrictive Enzymes to Make Cuts in
Both
• Mix Plasmid and Vector DNA Together and
Bond Via Ligase
• Clone
Overview of Process
Why Genetic Engineering?
• 3000 Known Genetic Diseases
Crop Improvement
• The improvement of crops
with the use of genetics
has been occurring for
years. Traditionally, crop
improvement was
accomplished by selecting
the best looking
plants/seeds and saving
them to plant for the next
year’s crop.
DNA Extraction
• DNA extraction is the first
step in the genetic
engineering process. In
order to work with DNA,
scientists must extract it
from the desired organism.
A sample of an organism
containing the gene of
interest is taken through a
series of steps to remove
the DNA.
Gene Cloning
• The second step of the
genetic engineering
process is gene cloning.
During DNA extraction,
all of the DNA from the
organism is extracted at
once. Scientists use gene
cloning to separate the
single gene of interest
from the rest of the genes
extracted and make
thousands of copies of it.
Gene Design
• Once a gene has been cloned, genetic engineers
begin the third step, designing the gene to work
once inside a different organism. This is done in a
test tube by cutting the gene apart with enzymes and
replacing gene regions that have been separated.
Transformation
• The modified gene is now
ready for the fourth step in
the process, transformation
or gene insertion.
• Since plants have millions of
cells, it would be impossible
to insert a copy of the
transgene into every cell.
Therefore, tissue culture is
used to propagate masses of
undifferentiated plant cells
called callus. These are the
cells to which the new
transgene will be added.
Backcross Breeding
• The fifth and final part of
producing a genetically engineered
crop is backcross breeding.
Transgenic plants are crossed with
elite breeding lines using
traditional plant breeding methods
to combine the desired traits of
elite parents and the transgene into
a single line. The offspring are
repeatedly crossed back to the elite
line to obtain a high yielding
transgenic line. The result will be
a plant with a yield potential close
to current hybrids that expresses
the trait encoded by the new
transgene.
Common Terms (FYI Only)
• Agbiotech = the agricultural arm of the biotechnology
industry
• Biotech = the biotechnology industry
• GE = genetic engineering/genetically engineered
• GM = genetically modified
• GMO = genetically modified organism
• Pharm crop = a GE crop that creates its own
pharmaceutical byproducts in virtually all parts of the
plant
• Transgenic = another name for GE
GMO / Genetically Modified
Organism
• A GMO is a plant, animal or microorganism (e.g.,
bacteria) that is created by means that overcome
natural boundaries.
• Genetic engineering involves crossing species
which could not cross in nature.
• For example, fish genes have been inserted into
strawberries.
• The most widely grown GE crops are soybeans,
corn, canola (rapeseed) and cotton. Nearly all GE
crops grown today are one of two varieties: "insect
resistant" and "herbicide tolerant" crops.
Good Reasons Do Exist
• For example, the splicing of a specific
flounder gene for producing a unique blood
"antifreeze" protein into tomatoes, to render
them frost resistant; splicing insect proteins
into zucchinis to create a taste and fragrance
that is repugnant to other insect pests; or
growing potatoes endowed with built-in
pesticides.
According to the FDA
• While the Food and Drug Administration
insists that foods produced by genetic
engineering are the same as foods from
traditional breeding, their own scientists
reported that, "the processes of genetic
engineering and traditional breeding are
different and... they lead to different risks."
GENETIC ENGINEERING: A
CAUTIONARY APPROACH
• The Institute of Science,
Technology and Public Policy has
taken a strong precautionary stand
on genetic engineering. In
collaboration with leading
scientists and other public service
organizations, it has launched a
nation-wide public awareness
campaign to alert the public about
the dangers of genetically
engineered foods, and is calling
for rigorous safety testing and
mandatory labeling of such foods.
Humans?
• The biotech industry's rationale for the
genetic engineering of humans is the
predisposition of human beings to certain
diseases. If such human frailties could be
fortified by genetically transplanting traits
of other animals, insects, bacteria or viruses,
then it might be possible for
biotechnologists to improve upon our
species.
The Argument
• Genetic surgery performed on fetuses would, with
high probability, infect the germ line (egg or
sperm) cells.
• As a consequence, any such genetic defects would
be passed on to future generations, causing
irreversible gene pollution and the potential for
new genetic diseases.
• In addition to the immediate and long-term gross
health risks posed by irreversible gene pollution,
we have no idea what the subtle effects of
incomplete or mutated human DNA will be on the
human race.
The Fact Exists That There Are Some Diseases Out
There We Cannot Cure Without Genetic
Engineering.
Take a Stand. Have a View.
But Ask Yourself…Would That View Change If It Were
Your Child?
Real Life
Example
SCID
Babies born without immune systems
quickly become ill during weaning when
the protection of their mother's milk –
which contains maternal antibodies –
begins to wear off. Without
transplant medicine of some kind, the
only way of keeping these children alive
is to cocoon them in a sterile
environment free of potentially lethal
microbes.
In the Sixties and Seventies, hospitals
put babies with severe combined
immune deficiency (SCID) in plastic
"bubbles" where the the air is filtered
and direct contact with the outside
world is minimized.
Paul Simon
Boy in the Bubble
Rhys Evans (April 2002 UK)
• Gene Therapy used to
cure a toddler of
SCID
• Took Bone Marrow
from the child, then
used a virus to carry a
new version of the
gene into the immune
cells from the
marrow.