A genetically modified organism (GMO) is any organism whose genetic material has been altered using genetic engineering techniques. The exact definition of a genetically modified organism and what constitutes genetic engineering varies, with the most common being an organism altered in a way that "does not occur naturally by mating and/or natural recombination".[1] A wide variety of organisms have been genetically modified (GM), including animals, plants, and microorganisms. Genetic modification can include the introduction of new genes or enhancing, altering, or knocking out endogenous genes. In some genetic modifications, genes are transferred within the same species, across species (creating transgenic organisms), and even across kingdoms. Creating a genetically modified organism is a multi-step process. Genetic engineers must isolate the gene they wish to insert into the host organism and combine it with other genetic elements, including a promoter and terminator region and often a selectable marker. A number of techniques are available for inserting the isolated gene into the host genome. Recent advancements using genome editing techniques, notably CRISPR, have made the production of GMOs much simpler. Herbert Boyer and Stanley Cohen made the first genetically modified organism in 1973, a bacterium resistant to the antibiotic kanamycin. The first genetically modified animal, a mouse, was created in 1974 by Rudolf Jaenisch, and the first plant was produced in 1983. In 1994, the Flavr Savr tomato was released, the first commercialized genetically modified food. The first genetically modified animal to be commercialized was the GloFish (2003) and the first genetically modified animal to be approved for food use was the AquAdvantage salmon in 2015.

1. Genetically Modified Organisms (GMO)
Introduction :-
• A genetically modified organism (GMO) is an organism whose genetic material has been
altered using genetic engineering techniques. These are also known as transgenic
organisms.
• GMOs are created in the laboratory using scientific methods like Recombinant DNA
technology and Reproductive cloning.
• In Recombinant DNA technology, one or more genes from an organism are inserted into
the DNA of another organism. On the other hand, reproductive cloning involves the
extraction of a mature somatic cell from the desired organism and is inserted into the egg
of the target organism that has its own nucleus removed.
• Organisms that have been genetically modified include micro-organisms such as bacteria
and yeast, plants, fish, and mammals etc.
• Source of genetically modified foods, and are also widely used in scientific research and
to produce useful goods other than food.
Basic Procedure for production of GMO :-
The process includes a foreign gene that is added to the host organism and this gene can be
derived from an unrelated species than a host organism. Steps involve:
1. Elimination (e.g., knock out animals): specific portion in the host organism is
knocked out to replace it with the desired gene.
2. Introduction of foreign DNA: then, introducing the desired gene from even an
unrelated species
3. Production of transgenic organism: it is the result of the successful introduction
of foreign DNA into a host organism know known as a transgenic organism. And
the introduction of genes is usually carried out in the early stages of the
development of the host organism.
Principle Objective Of Production :-
• The basic principle for producing a GMO was to add new genetic material into an
organism's genome.
• This is called genetic engineering and was made possible through the discovery of DNA
and the creation of the first recombinant DNA molecules by Paul Berg in 1972.
Genetically Modified Plants or Crops / Transgenic Plants :-
• Genetically modified crops are the crops whose genes are modified using genetic
engineering techniques. These are also called transgenic crops.

2. • The main goal of producing GMOs is to increase the yield of the crop and to produce
disease-resistant crops.
• An example of a genetically modified crop is Golden Rice. It was genetically modified to
generate beta-carotene twenty times more than the previous varieties of rice. Golden rice
is intended for Asia. One more rice variety was also created to fight iron deficiency. A
gene from the bean plant is taken and inserted into the rice gene, and the resultant rice
helps to fight iron deficiency.
• Another organism that was produced through genetic engineering is Arabidopsis
thaliana.
• Other examples are – Bt brinjal, Bt tomato, Bt cotton, GM maize, Soybean.
Genetically Modified Microbes :-
Bacteria : E. coli for insulin production
• Transformation: the process of introduction of foreign DNA into a cell,
• Requires a competent cell, which is introduced in E. coli using calcium chloride.
• After the treatment, foreign DNA becomes capable of introduction into the competent
cell and thus later integrate into the genome.
• Disadvantage: less efficient, require selection marker
• Advantage: easy to perform, cheap
• Herbert and Boyer in 1978 used the same competent cell of E. coli to produce insulin
which is used to cure diabetic patients.
Genetically Modified Mammals :-
• Ralph L. Brinster and Richard Palmiter developed the techniques responsible for
transgenic mice, rats, rabbits, sheep, and pigs in the early 1980s.
• They established many of the first transgenic models of human disease, including the first
carcinoma caused by a transgene.
• The process of genetically engineering animals is a slow, tedious, and expensive process.
However, new technologies are making genetic modifications easier and more precise.
Advantages of Genetically Modified Organisms (GMO)
• Better nutritional values
• Food has a longer shelf life
• Because of increased shelf life, it is easy to transport
• Reduced use of herbicides and pesticides
• Used in pharmaceutics, to produce vaccines, insulins, and disease treatment
• Transgenic mice have wide application in research
• Higher yield of crops
• The desired trait in crops can be monitored and controlled

3. Disadvantages of Genetically Modified Organisms (GMO)
• Associated ethical issue
• Can be complex to be understood for farmers
• Can introduce antibiotic resistance
• More legal liabilities for farmers growing GMO
• No independent research can be done
• Genes pass into other plants species
• Lack of awareness among consumers
• Introducing GM varieties in new habitats could result in the transfer of new genes to the
traditional varieties and wild relatives of the crop. It could also change ecosystems by
affecting nontarget organisms.