Genetic Engineering
What is genetic engineering?
Definition:
process of changing an
organism’s genetic material to
produce a new and useful result
This
results in a transgenic
organism
(organism containing
recombinant DNA)
Tobacco Plant that
has had a firefly gene
inserted into its cells,
so it “glows”.
Why make transgenic plants
and animals?
Food production
Make plants that are resistant to pesticides and/or diseases
(Round
-
up
®
ready crops, crops resistant to certain viruses)
Engineer food to stay fresh longer and ripen at the store
Engineer some animals to grow larger without using antibiotics or
growth hormone.
Protein production
Cows and goats could produce human proteins in milk
Even plants can be used to produce human proteins
Vitamin A in “golden rice”
Medical Research
Use the “glow” gene to follow the expression of another gene.
Edible vaccines.
How does genetic engineering work?
The desired (“donor”) gene is isolated
from the organism’s DNA using a
restriction enzyme
Bacterial plasmid (“cloning vector”) is
cut with
same
restriction enzyme
Sticky ends of desired gene and plasmid should be
complementary
Ligase (an enzyme) is added to help seal
sticky ends of plasmid and desired gene
together
Last step: put the recombinant plasmid back
into the bacteria
Example: Insulin Production
Protein that codes for insulin production is
cut from human DNA using restriction
enzyme (EcoRI)
Example: Insulin Production
Plasmid (from
E.coli
)
is also cut with EcoRI
Sticky ends are now
exposed on both
human DNA and
plasmid DNA
Example: Insulin Production
Ligase seals sticky ends
of desired DNA and
plasmid DNA
Recombinant DNA is
inserted into a
bacterium
Bacterium divides,
producing 100’s of
bacteria with the
desired gene.
Why insert recombinant DNA into a bacterium?
Bacteria reproduce rapidly (some every
20 minutes)
Inserted gene (e.g. insulin) is copied
(cloned) whenever bacteria make a copy of
the plasmid
Results in a large amount of desired
protein (insulin) in just a few days
How can you insert recombinant DNA into
a host cell?
Transformation:
use electricity, heat,
or CaCl
2
to “shock”
cell into taking up
plasmid
Microinjection:
inject plasmid DNA
directly into cell
using microneedle
How can you insert recombinant DNA into
a host cell?
Gene gun:
coat
tiny gold pellets
with recombinant
plasmid DNA and
“shoot” into cell
How can you insert recombinant DNA into
a host cell?
Viral vectors:
Desired gene is placed
into viral DNA and used to “infect” an
organism’s cells without causing disease
(virulence gene removed)
Enter the password to open this PDF file:
File name:
-
File size:
-
Title:
-
Author:
-
Subject:
-
Keywords:
-
Creation Date:
-
Modification Date:
-
Creator:
-
PDF Producer:
-
PDF Version:
-
Page Count:
-
Preparing document for printing…
0%
Σχόλια 0
Συνδεθείτε για να κοινοποιήσετε σχόλιο