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Basically, genetic engineering, also known as genetic modification or genetic manipulation, which represents the direct manipulation of an organism's genes employing biotechnology.
This is a set of technologies used to change the genetic makeup of cells, incorporating the transfer of genes within and across species boundaries to generate enhanced or novel organisms.
New DNA is attained by either isolating and copying the genetic material of interest using recombinant DNA strategies or by artificially synthesising the DNA.
A construct is generally created and employed to insert this DNA into the host organism.
The first recombinant DNA molecule was made by Paul Berg in 1972 by combining DNA from the monkey virus SV40 with the lambda virus.
As well as inserting genes, the phenomenon can be used to remove, or "knock out", genes.
The novel DNA can be inserted randomly, or targeted to a specific part of the genome.
Genetic engineering is a phenomenon that alters the genetic structure of an organism by either removing or introducing DNA.
Unlike traditional animal and plant breeding, that involves doing multiple crosses and then selecting for the organism with the desired phenotype, genetic engineering takes the gene directly from one organism and delivers it to the other.
This is much faster, can be used to insert any genes from any organism (even ones from different domains) and prevents other undesirable genes from also being appended.
Genetic engineering could potentially fix severe genetic disorders in humans by replacing the defective gene with a functioning one.[4]
It is an important tool in research that allows the function of specific genes to be studied.[5] 
Drugs, vaccines and other products have been harvested from organisms engineered to produce them.[6] 
Crops have been developed that aid food security by increasing yield, nutritional value and tolerance to environmental stresses. 
The DNA can be further introduced directly into the host organism or into a cell that is then fused or hybridised with the host.
This relies on recombinant nucleic acid techniques to form new combinations of heritable genetic material followed by the incorporation of that material either indirectly through a vector system or directly through micro-injection, macro-injection or micro-encapsulation. 
Genetic engineering does not normally include traditional breeding, in vitro fertilisation, induction of polyploidy, mutagenesis and cell fusion techniques that do not use recombinant nucleic acids or a genetically modified organism in the process.
However, some broad definitions of genetic engineering include selective breeding.
Cloning and stem cell research, although not considered genetic engineering, are closely related and genetic engineering can be used within them.
Synthetic biology is an emerging discipline that takes genetic engineering a step further by introducing artificially synthesised material into an organism.
Such synthetic DNA as Artificially Expanded Genetic Information System and Hachimoji DNA is made in this new field.
Thterms e next step is to isolate the candidate gene.
The cell containing the gene is opened and the DNA is purified.
The gene is separated by using restriction enzymes to cut the DNA into fragments or polymerase chain reaction (PCR) to amplify up the gene segment.
These segments can then be extracted through gel electrophoresis.
If the chosen gene or the donor organism genome has been well studied it may already be accessible from a genetic library.
If the DNA sequence is known, but no copies of the gene are available, it can also be artificially synthesised.
Once isolated the gene is ligated into a plasmid that is then inserted into a bacterium.
The plasmid is replicated when the bacteria divide, ensuring unlimited copies of the gene are available.
3.	Applications
The genetic engineering has various applications in medicine, research, industry and agriculture and can be used on a wide range of plants, animals and microorganisms. 
Bacteria, the first organisms to be genetically modified, can have plasmid DNA inserted containing new genes that code for medicines or enzymes that process food and other substrates. 
Plants have been modified for insect protection, herbicide resistance, virus resistance, enhanced nutrition, tolerance to environmental pressures and the production of edible vaccines. 
Most commercialised GMOs are insect resistant or herbicide tolerant crop plants.
Genetically modified animals have been used for research, model animals and the production of agricultural or pharmaceutical products.
The genetically modified animals incorporate animals with genes knocked out, increased susceptibility to disease, hormones for extra growth and the ability to express proteins in their milk.