Genetic transformation techniques

Table of Content
sIntroduction:................................................................................................................................................ 3
What is genetic engineering?....................................................................................................................... 3
History of genetic engineering:................................................................................................................... 3
Techniques of genetic engineering:.............................................................................................................4
Genome editing:...................................................................................................................................... 5
Homologous recombination:................................................................................................................... 5
Meganucleases and ZNF.........................................................................................................................5
TALEN and CRISPER............................................................................................................................5
Genetic transformation techniques:.............................................................................................................6
Indirect method:...................................................................................................................................... 7
Agrobacterium mediated gene transfer:...............................................................................................7
Direct gene transfer method:..................................................................................................................... 10
Physical gene transfer method:..............................................................................................................10
Electroporation:................................................................................................................................. 10
Particle bombardment:....................................................................................................................... 11
Microinjection:.................................................................................................................................. 11
Liposome mediated transformation:..................................................................................................12
Silicon carbide mediated transformation:..........................................................................................12
Chemical gene transfer method:............................................................................................................13
Polyethylene Glycol mediated transfer:.............................................................................................13
DEAE dextran mediated transfer:......................................................................................................13
Calcium phosphate co-operation mediated transfer:..........................................................................13
Conclusion:............................................................................................................................................... 13
References:................................................................................................................................................ 14

Table of figures:Figure 1: Genetic engineering in plants.......................................................................................................4
Figure 2: Gene transfer method in plant......................................................................................................7
Figure 3: Indirect gene transfer...................................................................................................................9
Figure 4: Electroporation........................................................................................................................... 10
Figure 5: particle bombardment gun.........................................................................................................11
Figure 6: microinjection............................................................................................................................. 11
Figure 7: Liposomes mediated transformation..........................................................................................12

Introduction:
Genetic engineering is a technique in which desired characteristics are introduced into an
organism in order to make it novel organisms. The main purpose of the genetic engineering is the
production of GMO’s (Genetically Modified Organisms). This technique mostly applied on
bacteria and plants. Its applications include production of genetically modified crops having
good yield and gene therapy to eliminate the diseases. The importance of this process is going up
day by day [1].
What is genetic engineering?
“Genetic engineering is a process in which gene of the organism is altered or change with the
organism in order to get the desired characteristics or phenotype of that organism and as a result
a novel organism will be created” [2].
This process is also known with two other names; one is genetic modification and the second one
is genetic manipulation. This process is called Genetic Modification because the characteristics
of that organism changed and it became novel or better one organism. The reason of this process
being called Genetic Manipulation is that, the genes or genetic makeup of the organism is being
manipulated with other. Lot of organisms have been using this technique that are following:
Bacteria
Animals such as fish, sheep, insects etc.
Plants (cotton, rice, soybean, maize, etc.)
Viruses [3].
History of genetic engineering:
About 1000 years ago, people harvest their crops and cultivate the food from crops and animals.
In 1942, corn was firstly introduced into the world that lead to development in the agriculture.
Through this way, the concept of selective breeding was introduced into the world. The

Figure 1: Genetic engineering in plants
discoveries that were made in 1900s paved the way for genetic engineering. In 1922, Robbin and
Kolte cultured root and stem tips.
In 1950, Barbara McClinton explains about the transposons. Transposons are the DNA sections
that move from one place or location of chromosome to another and this process is known as
jumping gene. She said that, this all jumping led to alteration of DNA.
When the DNA was discovered by Watson and Crick in 1953 then , a scientist with the name of
Kornberg made the DNA in test tube for the very first time in 1958 by extracting the DNA
polymerase from bacteria and then assembled the nucleotides of the DNA.
1n 1962, Osamu isolated the GFP (green florescence protein) from the jelly fish and introduced
it into a plasmid. In 1967, discovery of the DNA ligase was made. In 1968, restriction
endonucleases were discovered and purified in 1970 [4].
In 1973, genetic modification was done by Herbert and Stanley. A mouse is the organism that
was first genetically modified by Rudolf Jaensch, in 1974 [5].
In 1971, Takebe developed the first plant from the protoplast.
In 1982, Mary Dell created the first genetic engineered tobacco plat. In this process, a gene
resistant to bacterium was introduced into the tobacco plant to make it resistant to bacteria. This
achievement paved the way for the scientists to manipulate the genetic makeup of organisms [6].
In 1994, first genetically modified food i.e. tomato was brought into the market. This was done
to lower the ripening of tomato but the scientists didn’t get the results that they wanted. In 1996,
a sheep was cloned and named as dolly. In 2003, human genome was sequenced [7].
Techniques of genetic engineering:
The process of genetic engineering is usually
taking place with the help of other techniques or in
simple words, other techniques are also used in the
genetic engineering. If its method is discussed in
simple word, then according to this method first of
all, a gene is selected whose characteristics have to
be show in another organism. Then isolate the gene