1. Transgenic and Cloned
Organisms
By: Michael and Legae

2. Definition
• The term transgenic • Cloned organisms are
organism refers to an any organism whose
organism in which there genetic information is
has been a identical to that of a
deliberate/artificial parent organism from
modification of the which it was created.
genome.

3. How transgenesis works
• Foreign DNA is introduced into the organism and must then be
transmitted through the germ line so that every cell, including germ
cells, of the organism contain the same modified genetic material.
• If the germ cell line is altered, characters will be passed on to succeeding
generations in normal reproduction but if the somatic cell line alone is
altered, only the organism itself will be affected, not its offspring.
– **germ line: genetic material in a cell lineage that
is passed down through the gametes before it is
modified by somatic recombination or maturation.

4. There are three ways in which
transgenesis can be done.
DNA Microinjection ;
Retrovirus-mediated Gene Transfer
Embryonic Stem Cell-mediated Gene Transfer

5. DNA microinjection
• The DNA or selected gene is introduced by
microinjection through a fine glass needle into
the male pronucleus - the nucleus provided by
the sperm before fusion with the nucleus of
the egg.
• After fertilization the manipulated fertilized
ovum is transferred into the oviduct of a
recipient female, or foster mother that has
been induced to act as a recipient.

6. Embryonic stem cell-mediated gene
transfer
• This method involves prior insertion of the
desired DNA sequence by homologous
recombination into an in vitro culture of
embryonic stem cells.
• Stem cells are undifferentiated cells that have the
potential to differentiate into any type of cell
(somatic and germ cells) and therefore to give
rise to a complete organism. These cells are then
incorporated into an embryo at the blastocyst
stage of development.

7. Retrovirus-mediated gene transfer
• In this method the gene transfer is mediated by
means of a carrier or vector, generally a virus or a
plasmid. Retroviruses are commonly used as
vectors to transfer genetic material into the
cell, taking advantage of their ability to infect
host cells in this way. Offspring derived from this
method are chimeric, i.e., not all cells carry the
retrovirus.
• Transmission of the transgene is possible only if
the retrovirus integrates into some of the germ
cells.

8. For any of these techniques the
success rate in terms of live birth
of animals containing the
transgene is extremely low.

9. Uses of transgenic organisms
• Improving plants New plant varieties have been produced using
bacterial or viral genes that confer tolerance to insect or disease pests and
allow plants to tolerate herbicides, making the herbicide more selective in its
action against weeds and allowing farmers to use less herbicide.
• Improving livestock to produce animals that are larger and leaner,
grow faster and are more efficient at using feed, more productive, or more
resistant to disease.
• Pharmaceutical products many valuable pharmaceutical
products can now be made using transgenic animals such as mice, rabbits,
sheep, goats, pigs and cows. i.e haemoglobin as a blood substitute human
protein C, cystic fibrosis transmembrane conductance regulator (CFTR) for
treatment of CF, insulin for diabetes treatment, growth hormones for
treatment of deficiencies monoclonal antibodies vaccines (antigens).

10. Examples of transgenic organisms

11. Cloned Organisms
• Def: What exactly is cloning?
• Cloning is the creation of an organism that is an exact genetic copy of
another. This means that every single bit of DNA is the same between the
two.
• Methods:
Artificial Embryo Twinning Somatic Cell Nuclear Transfer

12. Artificial Embryo Twinning
• relatively low-tech version of cloning. • Artificial embryo twinning uses the
As the name suggests, it mimics the same approach, but it occurs in a
natural process of creating identical Petri dish instead of in the mother's
twins. body. This is accomplished by
manually separating a very early
• In nature, twins occur just after embryo into individual cells, and then
fertilization of an egg cell by a sperm allowing each cell to divide and
cell. In rare cases, when the resulting develop on its own. The resulting
fertilized egg, called a zygote, tries to embryos are placed into a surrogate
divide into a two-celled embryo, the mother, where they are carried to
two cells separate. Each cell term and delivered. Again, since all
continues dividing on its the embryos came from the same
own, ultimately developing into a zygote, they are genetically identical.
separate individual within the
mother. Since the two cells came
from the same zygote, the resulting
individuals are genetically identical.

13. Somatic Cell Nuclear Transfer (SCNT)
1] extract the nucleus of a somatic cell, a cell • An embryo is composed of cells that
which can come from anywhere in the contain two complete sets of
body, and insert it into an egg which has had
its nucleus removed. chromosomes. The difference between
http://learn.genetics.utah.edu/content/tech/cloning/whatiscloning/images/enucleation.mpg ;
fertilization and SCNT lies in where those
http://learn.genetics.utah.edu/content/tech/cloning/whatiscloning
/images/transfer.mpg two sets originated.
• In fertilization, the sperm and egg both
2] The egg is stimulated ( treated with
chemicals or electric current in order to contain one set of chromosomes. When
stimulate cell division) the sperm and egg join, the resulting
http://learn.genetics.utah.edu/content/tech/cloning/whatisclonin zygote ends up with two sets - one from
g/scnt.html the father (sperm) and one from the
3]it begins dividing and growing, developing mother (egg).
into an embryo. • In SCNT, the egg cell's single set of
chromosomes is removed and replaced by
4] It is then implanted into a gestational the nucleus from a somatic cell, which
surrogate and carried to term.
already contains two complete sets of
chromosomes. Therefore, in the resulting
How does SCNT differ from the natural embryo, both sets of chromosomes come
way of making an embryo?
from the somatic cell.

14. Therapeutic Cloning

15. Question: Are Clones Normal?
• Essentially, all somatic cells in a given organism, other than
RBCs, have a nucleus with chromosomes that contain exactly the
same DNA sequence. But there are hundreds of different kinds of
cells in the body, and they are different because each cell type
selectively uses different parts of the genome.
• The DNA in the nucleus transferred into an oocyte requires
reprogramming, for example, from functioning as a skin fibroblast
to functioning as a one-cell embryo. Little is known about how this
reprogramming occurs, except that it often does not get done
correctly. This is not surprising, because the one-cell embryo
normally programs sperm and oocyte DNA, not DNA from somatic
cells.
• Most malprogrammed embryos result in embryonic or fetal death.
With current SCNT procedures, this result occurs in nearly 90% of
embryos; it is one of nature’s ways of weeding out problems!

16. • two major problems: few clones survive to
term and those that do are grotesquely
large.
1. poor survival rate is influenced by the
genetic background of the donor cell
2. the gross overgrowth of clones results
from the actual procedure of cloning.
http://www.sciencedaily.com/releases/2001/05/010511073756.htm
• “While clones are genetically
identical, physical characteristics such as
size, weight and hair type; and
behavioural characteristics may not be
the same because the DNA has been
modified during the cloning process in
such a way that it affects the activity of
certain genes.”
http://www.sciencedaily.com/releases/2003/04/030416085546.htm
• Scientists have known for some time that
clones’ observable characteristics and
traits can vary, and this variation can be
passed on to the next generation.
• the genomes of cloned plants carry
relatively high frequencies of new DNA
sequence mutations that were not
present in the genome of the donor plant.
http://www.sciencedaily.com/releases/2011/08/110804212931.htm

17. Cloning and its uses
• extinct and near-extinct species could • highly prized domesticated animals
be reproduced for zoos and/or could be duplicated to improve food
reintroduction into the wild; yields in the dairy, beef, pork, and
• http://blogs.discovermagazine.com/sciencenotfiction/2009/04/22/
waking-and-cloning-baby-mammoths/#.UMDayIP0CSc
poultry industries;
• and winning race animals could be • Commonly employed in post-stages
cloned for competition. of transgenesis
• Eliminates the need for third-party • Therapuetic cloning: production of
egg or sperm for: human embryos for use in research.
To harvest stem cells that can be
– Couples who (i) have a genetic
used to study human development
disorder and (ii) reject genetic
and to treat disease.
screening and selective abortion.
• Organ cloning- type of cloning that
– Gay/lesbian parents
does not currently exist but is
– Couples one of whom lacks viable theoretically possible. With organ
eggs or sperm cloning, human organs could be
grown from a small sample of cells
for a specific patient.

18. references
• Transgenesis
• http://www.actionbioscience.org/biotech/margawati.html
• http://www.nature.com/scitable/topicpage/genetically-modified-organisms-gmos-transgenic-crops-and-732
• http://www.wisegeek.com/what-are-transgenic-organisms.htm
• Cloning
• http://learn.genetics.utah.edu/content/tech/cloning/whatiscloning/
• http://www.sciencedaily.com/
• http://www.ornl.gov/sci/techresources/Human_Genome/elsi/cloning.shtml
• http://www.wisegeek.com/what-are-some-benefits-of-cloning.htm