2. CONTENTS
● Meaning and basic
understanding
● History
● Production methods and
techniques
● Present scenario
● Importance of transgenic
organisms and their
applications
● Impacts on various factors
3. Definition
Transgenesis (also called genetic
modification) is the process of
introducing a gene (transgene)
from one organism to genome of
another organism.The aim is that
the resulting transgenic organism
will express the gene and exhibit
some new property or
characteristics.
4. Basic terms to know
● Transgene - foreign gene or genetic material that has been
transferred naturally or using genetic engineering techniques
from one organism to another.
● Genome - the complete set of genes or genetic material
present in a cell or organism.
● Plasmid - a small, extrachromosomal DNA and can replicate
independently
● Restriction enzyme - a protein that recognises a specific,
short nucleotide and cuts DNA only at specific site known as
restriction site or target sequence.
5. HISTORY
The first GMO was created in 1973 Stanley
N.Cohen and Herbert Boyer. Demonstrating the
creation of a functional organism that combined
and replicated genetic information from different
species.
The first transgenic animals were mice created by
Rudolf Jaenisch in 1974. Jaenisch successfully
managed to insert foreign DNA into the early stage
mouse embryos;the resulting mice carried the
modified gene in all their tissues.
● Injecting leukemia genes to early mouse
embryos using a retrovirus vector, proved the
genes integrated not only to the mice
themselves, but also their progeny.
6.
7. The first two commercially prepared products from DNA recombinant
technology were insulin and human growth hormone,both of which were
cultured in E.coli bacteria.
8. Production methods and techniques
There are 3 principal methods used for production of transgenic animals:
❏ DNA Microinjection
❏ Embryonic stem cell-mediated gene transfer
❏ Retrovirus-mediated gene transfer
9. Microinjection.
Microinjection is a
technique of delivering
foreign DNA into a living
cell (a cell, egg, oocyte,
embryos of animals)
through a glass
micropipette. One end of
a glass micropipette is
heated until the glass
becomes somewhat
liquified. It is quickly
stretched which forms a
very fine tip at the heated
end.
10. 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
(ES) cells. ... These cells are
then incorporated into an
embryo at the blastocyst stage
of development. The result is a
chimeric animal.
Chimera:A genetic chimerism or chimera is a
single organism composed of cells with more than
one distinct genotype.
11. This gene transfer is
mediated by means of a
carrier or vector, generally a
virus or a plasmid.
Retroviruses are commonly
used as vectors. The killed
virus is replication defective.
The virus gene is replaced
with trans-gene. The trans-
gene is delivered to the host
cell by transfection (gene
therapy)
Retrovirus mediated gene
transfer
12. In present world we use transgenic organisms a lot more than we realize or pay attention. Some of
modern uses are mentioned as :
Transgenic pets: Glow-in-dark fish
Ever have one of those groovy posters that glows under a black light? Well, move that black light over to the
aquarium — there’s a new fish in town. Originally derived from zebrafish, a tiny, black-and-white–striped native of
India’s Ganges River, these glowing versions bear a gene that makes them fluorescent. The little, red, glow-in-the-
dark wonders (referred to as GloFish) are the first commercially available transgenic pets.
Zebrafish are tried-and-true laboratory veterans-they even have their own scientific journal! Developmental
biologists love zebrafish because their transparent eggs make it simple to observe development. Geneticists use
zebrafish to study the functions of all sorts of genes, many of which have direct counterparts in other organisms,
including humans. And genetic engineers have taken advantage of these easy-to-keep fish, too; scientists in
Singapore saw the potential to use zebrafish as little pollution indicators. The Singapore geneticists used a gene
from jellyfish to make their zebrafish glow in the dark. The action of the fluorescent gene is set up to respond to cues
13. The transgenic zebrafish then provide a quick and easy to read signal: If they glow, a pollutant
is present.
14.
15. Another potential use for transgenic insects
would be to release of millions of
transgenically infertile bugs that attract the
mating attentions of fertile ones. The matings
result in infertile eggs, reducing the
reproduction of the target insect population.
This is an especially appealing idea when
used to combat invasive species that can
sweep through crops with economically
devastating results.
16. Transgenic bacteria
Bacteria are extremely amenable to transgenesis. Unlike other transgenic organisms,
genes can be inserted into bacteria with great precision, making expression far easier to
control. As a result, many products can be produced using bacteria, which can be grown
under highly controlled conditions, essentially eliminating the danger of transgene escape.
Many important drugs are produced by recombinant bacteria, such as
insulin for treatment of diabetes, clotting factors for the treatment of
hemophilia, and human growth hormone for the treatment of some
forms of short stature. These sorts of medical advances can have
important side benefits as well:
17. ● Transgenic bacteria can produce much greater volumes of proteins than traditional methods.
● Transgenic bacteria are safer than animal substitutes, such as pig insulin, which are slightly
different from the human version and may therefore cause allergic reactions.
18. Transgenic plants
Plants are really different from animals, but not in the way you may think. Plant cells are totipotent,
meaning that practically any plant cell can eventually give rise to every sort of plant tissue: roots,
leaves, and seeds. When animal cells differentiate during embryo development, they lose their
totipotency forever (but the DNA in every cell retains the potential to be totipotent). For genetic
engineers, the totipotency of plant cells reveals vast possibilities for genetic manipulation.
Much of the transgenic revolution in plants has focused on moving genes from one plant to
another, from bacteria to plants, or even from animals to plants. Like all transgenic organisms,
transgenic plants are created to achieve various ends, including nutritionally enhancing certain
foods (such as rice) or altering crops to resist either herbicides used against unwanted competitor
plants or the attack of plant-eating insects.
19.
20. IMPORTANC
E
Medical importance
Transgenesis has contributed a lot in field of medicine as it is used to
discover some drugs,to see the impacts of some drug or vaccine and so
on.Their uses in medicine are unlimited.
❏ GENE THERAPY OF HUMANS:
Human gene therapy is the process in which by using the technique of
gene therapy in which healthy genes are inserted in the person’s body
in place of defective genes.Defective genes do not function properly
and cause diseases in the body.plasmids and vectors are used to
carry healthy genes.Transgenic animals could play vital role in the
treatment of almost 5000 genetic disorders.For example, the
scientists of Finland have developed a calf which carries a gene.The
gene is responsible for making a substance which provides the
growth of RBCs in humans.
21. ❏ XENOTRANSPLANTATION:
There are a lot of people in the world who die every year because of
organ failure.Some people have problems in their kidneys,, some in
lungs etc. In UK alone , almost 5000 organs are needed for the
patients. Scientists have successfully done experiments in pigs and
have developed human organs.Though their is a protein in pig which
cannot be accepted by human immune system but scientists are
working on this problem and are trying to replace this protein with
human protein.
❏ PHARMACEUTICALS:
Scientists have produced insulin, growth hormones and blood clotting
factors in the transgenic animals.These are obtained from cow’s milk
and are very useful for human health.Blood clotting factor can be
beneficial for
Patients of haemophilia because they lack the ability to clot the blood.
Similarly milk is being obtained from goats or sheep through
transgenesis to treat diseases like cystic fibrosis and phenylketonuria.
22. Agricultural Importance:-
❏ Breeding:-
It is the culture of all farmers to breed animals selectively so that healthy animals can be
obtained that have the traits required by the farmers, for example, increased amount of milk
and healthy meat. Though traditional breeding is also common but it gives slow results as it is
a time consuming method. Molecular biology has made it possible to develop such
techniques which give better results in a short time. It is also beneficial for farmers in the
sense that farmer can get higher yield in a short time.
❏ Disease Resistance:-
Scientists are doing research on making such animals which are disease resistant. Diseases
like influenza can cause damage to the animal body that is why genes are inserted in pigs
which show resistant against this disease. farm animals are more susceptible to influenza as
they live in groups and disease spreads from one animal to the other.
❏ Quality:-
Quality is another factor which farmers want to increase. Transgenic cows are able to produce
milk which has more nutritional value than an ordinary cow's milk. Some farmers tried to use
growth hormones in animals but they didn't succeed in getting the desired results.
23. Industrial Importance:-
Two scientists of Canada have successfully inserted spider genes into goats
which are lactating. now it is possible that along with the milk production,
goats will also produce silk which is a light flexible material used to make
army uniforms, tennis rackets and medical microsutures. For the safety of
chemicals, scientists have produced toxicity sensitive transgenic animals.
Many proteins have produced by using transgenic animals which in turn
convert into enzymes to perform different functions in the body.