WHAT DOES IT MEAN TO
*Cloning: Reproducing genetically identical
copies of DNA, Cells organisms through some
*To "clone a gene" is to make many copies of it – for
example, by replicating it in a culture of bacteria.
*Duplicating a person e.g. identical twins is called
*Duplicating part of a person e.g. a heart or liver,
or even just a few cells is called “Therapeutic”
cloning (gene therapy).
*Cloned gene can be a normal copy of a gene or a
cloned gene can be an altered version of a gene.
*Otherwise, the organisms are called transgenic
organisms – these organisms today are used to
produce products desired by humans.
Cloning a human gene
* Scientists can use two
procedures to clone DNA.
A. Recombinant DNA (rDNA)
B. Polymerase chain reaction
A. Recombinant DNA (rDNA)
Recombinant DNA technology is used to
produce large quantity of insulin.
Recombinant: The creation of new combinations
of DNA segments that is not found together in
THE PROCESS OF rDNA:
Isolate DNA Cut with restriction enzymes
Ligate into cloning vector transform recombinant
DNA molecule into host cell each transformed cell
will divide many, many times to form a colony of millions of
cells, each of which carries the recombinant DNA molecule
1. DNA that codes for the production of insulin is removed from the
chromosome of a human pancreatic cell.
2. Restriction enzymes cut the gene from the chromosome (isolating
the gene for insulin)
3. A plasmid (acting as a vector/carrier of new gene) is removed from
the bacterium and cut open with a restriction enzyme to form
4. Ligase (enzyme) is added to join the insulin gene to the plasmid of
the bacterium cell - forming recombinant DNA.
5. The recombinant DNA can then be reinserted into the bacterium,
the bacterium will then produce more insulin, therefore cloning
6. When the bacterium reproduces it makes the insulin inserted into
7. The bacteria are kept in huge tenks with optimum pH,
temperature and nutrient values, where they multiply rapidly,
producing enormous amounts of insulin, this is then purified and
B. Polymerase chain reaction (PCR)
•PCR – Used in genetic profiling.
•To solve crimes – criminals usually leave
DNA evidence at the scene of the crime in the
form of saliva, blood, skin, semen and hair.
•These all contain DNA. If only a little bit of
DNA is found or the DNA is old, we can make
copies of the available DNA by means of PCR.
*From the DNA produced through PCR, DNA
fingerprint can be generated.
1. Sample containing DNA is heated in a test
tube to separate DNA into single strands.
2. Free nucleotides are added to the test
tube with DNA polymerase (enzyme), to
allow DNA replication.
3. DNA is cooled to allow free nucleotides
to form a complementary strand along side
each single strand.
4. In this way the DNA is doubled giving
sufficient amount of DNA to work with.
• Today transgenic bacteria, plants and animals
are called genetically modified organisms
• The products that GMO’s produce are called
GENETICALLY MODIFIED BACTERIA
• Recombinant DNA is used to make transgenic
• They are used to make insulin, clotting factor
VIII, human growth hormone and hepatitis B
• Transgenic bacteria is used to protect the
roots of plants from insect attack, by
producing insect toxins.
GENETICALLY MODIFIED PLANTS
• Example = pomato
• Genetically modified to produce potato's
below the ground and tomato's above the
• Foreign genes transferred to cotton, corn, and
potato strains have made these plants
resistant to pests because their cells now
produce an insect toxin.