Genetic Engineering Definition - MCVSD

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12 Δεκ 2012 (πριν από 4 χρόνια και 11 μήνες)

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What is…

…genetic engineering?

Genetic Engineering

Definition
: The group of applied techniques of genetics
and biotechnology used to directly manipulate genetic
material from one or more species of organisms to get
a desired product (protein)

Do you know anyone who is diabetic?


Questions to Ponder:


What is the cause of the disease?


What is the treatment for this disease?


Where does the treatment (insulin) come
from?


How is rDNA (recombinant DNA)
technology used to make human insulin?

The Cause of the Disease


inability of pancreas to produce insulin


insulin required to metabolize sugar


type 1: gene required to make insulin is
faulty

Treatment


modified diet


Minimal to no sugar


injection of hormone insulin

Source of insulin


Before recombinant DNA (rDNA)


extraction from animal (pig, cow)


extraction from human pancreas


After rDNA


Ely Lily Co.
--
> produce human insulin
using E.coli as production factories


HOW?

Production of human insulin


E.coli

cells have two types of DNA


chromosomal


plasmid


circular DNA found in cytoplasm


serves as insertion site for human insulin gene


Plasmids

make good vectors


Self replicates


Contains a promoter
region


Reasonable size and
circular


Easily identifiable

Production of human insulin


Step 1:


Human gene for insulin is “cut” from
human chromosome


“cutting” accomplished by chemical
scissors
-
>
restriction enzymes



Occur naturally in bacteria to attack
viruses


Recognize a specific sequence of bases
and cut the DNA backbone


recognition sites
--
>
palindromes


sequences are the same but run in opposite
directions


first strand: 5’ to 3’


second strand: 3’ to 5’


Enzymes are named from the organism
they are isolated from


EcoR1 (GAATTC)


Sau3A (GATC


What are Restriction Enzymes?

What are

sticky ends?


Definition
: unpaired nucleotides
remaining attached to DNA fragment
following digestion by restriction
enzyme


When 2 sequences are cut with
SAME
enzymes

-
> “sticky ends” are
complimentary


fragment of one plasmid can “splice”
into another


DNA ligase

then links the DNA
segments

Production of human insulin


Step 2:


Plasmids removed from E.coli cells


Plasmids opened using
same

restriction enzyme


Step 3:


combine cut plasmid and human insulin gene
(human insulin gene called
foreign DNA
)


Step 4:


recombinant
plasmid (part bacterial, part
human) is produced


plasmid now contains gene for insulin





Production of human insulin


Step 5:


recombinant plasmid is
inserted back into E.coli cells


The E.coli cells are now
called transformed.


Transformation
: a form of
genetic change in which the
genetic material carried by an
individual cell is altered by
incorporation of foreign DNA
into its genome.


We carry out transformations
in the laboratory by inserting
recombinant DNA into
competent cells.



Production of human insulin


Step 6:


bacteria containing
recombinant plasmids
multiplied in fermentation
tanks


Step 7:


human gene product is
isolated from bacteria


Step 8:


human insulin is ready for
injection into patient



Recombinant DNA Technology


Definition
:

insertion or modification of genes to
produce a desired product (protein)

Why is it important?


Purify protein


Generate more copies of a particular
gene: “amplify DNA”


Research gene function and regulation

Checkpoint

What do you need to make

recombinant DNA?

Transgenic Organisms


Contain genes from another species; a
gene from one organism is inserted
into another


Transformed cells
: cells that contain
genes from another organism; contain
DNA that is not their own.


Often referred to as
“GMO”s

=
genetically modified organisms

Transgenic Organisms


Animals


Used to


study genes


improve food supply


future: produce human protein


Examples


mice with human genes
-
> study immune system of
humans in mice

Transgenic Organisms


Animals


Plants


large part of food supply


benefits


plants produce natural
insecticide


plants resist weed
killing chemicals


example: rice containing
vitamin A “Golden Rice”


synthesize beta
carotene


Transgenic Plant: Vaccines


Idea: express vaccine in
banana


Very low cost: can grow
and afford in developing
countries


Eaten uncooked so
vaccine not degraded


Palatable to children


Potential problem:
digestion of vaccine in
intestinal tract

Transgenic Organisms



Animals


Plants


Microorganisms


reproduce rapidly, easy to grow


bacteria transformed with genes
for human protein
--
> produce
important compounds cheaply
and in large quantity


insulin (diabetes)


growth hormone (development)


clotting factor (hemophilia)