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Recombinant DNA
Technology
Bacterial Transformation &
GFP
Frederick Griffith - 1928
Plasmid: small, usually
ring-shaped molecule of
deoxyribonucleic acid
(DNA),
Plasmids are present in
almost all bacteria and
may also be found in
some yeasts and other
fungi, protozoa, and even
some plants and animals.
They are separate from
chromosomes.
Plasmids generally carry
fewer genes than do
chromosomes, and the
genes that they carry are
useful, but not essential,
to the survival of the cell.
Most bacteria have only
one chromosome under
normal circumstances,
but may contain 1 to 100
or more copies of a given
plasmid.
Example:
pAmp
Plasmid
Replication Site
Recombinant DNA, like most other
DNA technologies, relies on
restriction enzymes, specialized
enzymes that act like molecular
scissors to cut DNA strands at certain
points in a base sequence, which may
be four to eight bases long. This
creates “sticky ends.”
Another enzyme, called DNA ligase,
glues an isolated gene to a vector—a
fragment of DNA that is able to transfer
from one organism to another
(plasmids).
In this way, scientists cut and paste
pieces of DNA from different sources
together to create molecules that will
then be known as recombinant DNA.
9 minutes
The ability to combine human and bacterial DNA
has given rise to a number of medical advances.
The first commercial use of a recombinant
plasmids came in 1982, when scientists created
a genetically engineered bacterium able to
produce human insulin.
Insulin is a hormone that helps regulate blood
sugar and is needed by many people with
diabetes.
Plasmid Map (Simple)
*ORI is the origin.
Plasmid Maps
Growth and Purification of
Plasmids
Extraction
Transfection
Plasmid growth
in bacteria
Purification of
plasmid
Recombinant DNA Technology
and Vaccine Development
In vitro antigen
production
CHO, yeast,
or insect cells
Vaccine vector
In vivo
antigen
production