Genetic Engineering: Definition, Applications, History, Evolution, Principles, Tools and Techniques l Comprehensive Overview

Genetic Engineering

Genetic Engineering is a scientific technology to copy, change or replace the genetic structure of any organism. In genetic engineering, the structure of genetic material DNA or RNA is modified to attain desirable features in certain animals, plants or microorganisms. For instance, to make a crop disease resistant to certain pests or for a variety of pest attacks, a gene that makes a special killer protein is inserted into the original DNA of the plant or some other organism. 

Also, some desired traits can be introduced to a plant or animal species through the techniques of genetic engineering by inserting the gene related to that trait. The individual with or without the gene or with newly packed Genetic makeup is called Genetically modified organisms or GMOs. Genetic Engineering has applications ranging from plant quality enhancement to making insulin or some drugs. 


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Definition of Genetic Engineering

Genetic Engineering involves various techniques like recombinant DNA technology and CRISPR in which genetic makeup is altered, replaced or deleted in order to achieve desirable characteristics in an organism. In genetic engineering, a host organism is involved in which genetically modified DNA or recombinant DNA is introduced after the modifications.

If this DNA is not the original DNA of the host then the host is called transgenic. For example, a gene that makes insulin is inserted into a bacterial plasmid using tools and techniques of Recombinant DNA technology. Now this plasmid or secondary bacterial DNA is transferred to the bacterial cell. And now bacteria works as an insulin factor for humans. 


Historical Background and Evolution

Genetical Engineering has a long history starting from the discovery of DNA to CRISPR techniques, this field has its own ups and downs with a lot of accomplishments. Holding a rich lineage in gene editing and the formation of useful products and organisms for human benefit, modern genetic engineering even paves the way to treat deadly and almost untreatable diseases like cancer and genetic disorders. Here’s the historical background with multiple discoveries along the way in the field of genetic engineering. 

Year Milestone Description
Pre-1960s The Precursor to Gene Editing History The groundwork for genetic engineering is laid through various scientific discoveries and experiments.
1953 Discovery of the Double Helix James Watson and Francis Crick elucidate the structure of DNA, unveiling its double helix configuration.
1958 DNA is Made in a Test Tube for the First Time Scientists demonstrate the synthesis of DNA molecules in vitro, a significant breakthrough in molecular biology.
1960s Discovering and Linking DNA Research efforts focus on understanding and manipulating DNA, laying the foundation for genetic engineering.
1962 Jellyfish Protein Turns Into a Tool to Observe Invisible Cellular Processes The discovery of green fluorescent protein (GFP) enables visualization of cellular activities.
1967 DNA Ligation Links DNA Fragments Together Techniques for joining DNA fragments are developed, facilitating the creation of recombinant DNA molecules.
1968 Discovery of Restriction Enzymes The identification of restriction enzymes enables precise DNA cutting, a pivotal development in genetic engineering.
1970s Genetic Engineering Takes Off Unexpectedly Rapid advancements in genetic engineering techniques and applications redefine biotechnology.
1970 Purification of Type II Restriction Enzymes Type II restriction enzymes are purified, leading to their widespread use in DNA manipulation.
1971 Gene Splicing Experiment Paves the Way for Recombinant DNA (rDNA) Scientists successfully splice together DNA from different sources, demonstrating the potential of rDNA technology.
1971 Type II Restriction Enzymes Used for Mapping DNA Restriction enzymes are employed in DNA mapping, aiding in the understanding of genetic structure and function.
1972 Recombinant DNA (rDNA) is Created The first recombinant DNA molecule is constructed, marking a milestone in genetic engineering.
1974 National Academy Moratorium on Genetic Engineering Experiments Concerns over the safety and ethical implications of genetic engineering lead to a temporary halt in research.
1975 Hybridoma Technology Revolutionizes Diagnostics The development of hybridoma technology enables the production of monoclonal antibodies for diagnostic purposes.
1980s Bringing Vaccines & Treatments to Humans Genetic engineering applications expand to include the production of therapeutic proteins and vaccines.
1981 The First Transgenic Animal Transgenic animals, containing foreign DNA, are generated for research and biotechnological applications.
1982 First Genetically Engineered Human Drug – Synthetic Insulin Synthetic insulin, produced using genetically engineered bacteria, becomes the first human drug of its kind.
1983 The Development of the Polymerase Chain Reaction (PCR) PCR revolutionized molecular biology by enabling the amplification of DNA sequences with high precision.
1985 Discovery of Zinc Finger Nuclease (ZFN) Zinc finger nucleases are discovered, providing a novel tool for targeted genome editing.
1986 First Recombinant Vaccine for Humans is Approved The first recombinant vaccine, produced using genetic engineering techniques, receives approval for human use.
1988 The First Bt Corn Appears in Fields Bt corn, engineered to express insecticidal proteins, is commercially cultivated for pest control.
1990s Cloning and GMOs The 1990s witness significant advancements in cloning technology and the commercialization of GMOs.
1993 Discovery of the Principles of CRISPR CRISPR-Cas systems are discovered in bacteria, revealing their potential for genome editing applications.
1994 A Tomato Engineered to Stay Ripe is Brought to Market The first genetically modified tomato, engineered for prolonged ripeness, is introduced to the market.
1996 The Cloning of Dolly the Sheep Dolly the sheep becomes the first mammal cloned from an adult somatic cell, sparking ethical debates.
1999 History of Genetic Engineering in Humans is Made when the First Human Chromosome is Sequenced The sequencing of the human chromosome marks a significant milestone in understanding human genetics.
2000s The Human Genome is Mapped: New Regulations are Set The completion of the Human Genome Project leads to new regulations and ethical considerations in genetic research.
2001 The First Gene-Targeted Drug Therapy is Approved Gene-targeted therapies, tailored to individual genetic profiles, gain approval for clinical use.
2003 Sale of the Glo-Fish as a Pet for the Home Glo-Fish, genetically modified zebrafish, are sold as pets, sparking interest in bioluminescent organisms.
2006 FDA Approval of the First Preventative Cancer Vaccine The first cancer vaccine, targeting human papillomavirus (HPV), is approved for preventive use.
2006 First Induced Pluripotent Stem Cells (iPSCs) Induced pluripotent stem cells are generated, offering a potential alternative to embryonic stem cells.
2010-2020 The New Era of FDA-Approved Therapies The 2010s witnessed a surge in FDA approvals for genetic engineering-based therapies and treatments.
2010 The World’s First Synthetic Life Form Scientists create the first synthetic organism with a completely artificial genome.
2011 Discovery of TALENs Transcription activator-like effector nucleases (TALENs) are discovered, expanding the toolkit for genome editing.
2012 Discovery of CRISPR Genome Engineering Tool CRISPR-Cas9 emerges as a revolutionary genome editing tool, offering simplicity and precision in DNA manipulation.
2013 Showed CRISPR Utility in Eukaryotic Cells CRISPR-Cas9 is demonstrated to function effectively in eukaryotic cells, opening up new possibilities for gene editing.
2014 Identifying the Possibility of a Gene Drive Scientists explore the potential of gene drives for controlling or modifying populations of organisms.
2015 First GMO Salmon Sold in Canadian Markets Genetically modified salmon, engineered for faster growth, is sold for consumption in Canadian markets.
2015 A Human Embryo is Edited with CRISPR The first successful editing of a human embryo using CRISPR-Cas9 technology is reported.
2017 First CAR T Therapy for Cancer is Approved Chimeric antigen receptor (CAR) T-cell therapy receives approval as a groundbreaking treatment for cancer.
2018 First Human Trials for CRISPR


Principles, Techniques and Tools 

Genetical Engineering involves various processes in order to alter or modify the genetic sequence of some organism. Genetic engineering in voice these three major steps. 

  1. Extraction of a desired gene that possesses a special trait (target gene) from an organism. 
  2. Inserting the desired chain into the secondary or main DNA of another organism to make copies 
  3. Identification of modified genetic material and polymer chain reaction. 


Techniques of Genetic Engineering

There are several major techniques of genetic engineering:-

  • Gel-Electrophoresis in which segregation of DNA or RNA molecules is possible by movement under the charged field between electrodes. To cut down the DNA or RNA sequence it is necessary to isolate and purify it. 
  • To isolate and segregate chromosomes fluorescence activities cell technique is used along with the gel electrophoresis. 
  • The blotting technique is used to identify the main gene or protein. There are many types of these techniques including Northern blotting for RNA, southern blotting of DNA, dot blotting for RNA and DNA and western blotting for protein identification. 
  • To understand the functions and inherited disorders in individual DNA sequencing techniques are used. 
  • Pyrosequencing and DNA check techniques are useful for the same purpose. They are alternative techniques of DNA sequencing. 
  • Using laboratory techniques chemical synthesis of DNA is possible 
  • Recombinant DNA technology in cutting and inserting a foreign gene into DNA for a special purpose. This technique has been described in detail in this article. 
  • Polymerase chain reaction or PCR to make multiple copies of DNA or some gene. 
  • Gene cloning can make multiple identical copies of a specific gene to use or study 
  • CRISPR-Cas9 to edit a specific gene from a DNA sequence using cutting and modifying techniques 
  • Genomic sequencing can analyze the DNA sequence and help in the genetic modification of an organism. This technique is being used in humans to know the entire human DNA sequence and genetic abnormalities. 


Some Important Terms 

  • Recombinant DNA: the altered genetic material of the target organism with a small or big amount of inserted gene. 
  • Genetically modified organism (GMO): an organism with functioning altered DNA or gene. 
  • Plasmids: double-stranded circular secondary DNA bacteria that are being used in multiplication and inflation of desired genes. 

Tools of genetic engineering

Tools used in Genetic Engineering

In the recombinant DNA technology of genetic engineering, the phenotype that is physical characteristics of an organism is altered into the desirable characteristics using a vector. Now this cloning vector is inserted into the genome of the organism and then multiplied. So in this process, we basically make multiple copies of a gene of interest through inserting it into a foreign DNA. In this process, the following tools and techniques are used.


1. Restriction Enzymes

 The restriction enzymes are also called molecular scissors. There are two types of restriction enzymes, a) Restriction Endonuclease enzyme b) Restriction Exonuclease enzyme. The main function of restriction is endonuclease or exonuclease enzymes to cut the DNA from the special locations to get our desired gene. 

2. Vectors

The vector is responsible for carrying and multiplying the desired jeans in a foreign atmosphere. Devkas is the vehicle to carry desired jeans into the host organism. The main examples of the vectors are bacteriophages and plasmids; they both are used in the majority of cases of genetic Engineering. The bacteriophage is a virus that kills bacteria. It inserts its genetic material into the bacterial cell through attack. The plasmids are secondary genetic material of a bacteria. 

3.Host organism

As the name suggests the host organism except the genetically modified vector DNA carrying out desired genes. There are multiple methods to insert a vector into the host for example biolistic or gene gun, alternate cooling and heating methods, using calcium in for insertion and micro injection etc. 

4.DNA Ligase

DNA liga is the molecular glow to take for NDA and cloning vector genetic sequences. To work properly it is necessary to cut both the vector and gene with the same DNA Ligase. 

5. Reverse Transcriptase

This enzyme can synthesize DNA molecules from the RNA molecule. 

6. DNA Gyrase 

DNA car is a bacterial enzyme that prevents DNA from recoiling or supercoiling. 


Process of genetic engineering

  1. Isolation of DNA molecules with desired Gene.
  2. Cutting the desired gene with the help of molecular scissors.
  3. Insertion (ligation) desired Gene into the appropriate vector. 
  4. Transformation and selection of converted vectors from not converted vectors.
  5. Expression of genes via multiplication. 



In Medicine

  • Multiple applications in the field of medicine from the manufacturing of critical drugs to the creation of model animals that can intimate human emotions. 
  • It has large applications in gene therapy and human growth hormone synthesis.
  • Using various tools of genetic engineering follicle stimulating hormones can be developed to inject 10 milk-producing animals to produce more milk and progeny. 
  • To cover the necessity of human albumin biotechnologicals can do miracles like in the insulin case. 
  • It can develop monoclonal antibodies and antihemophilic factors. 
  • Multiple vaccines have been developed using its application and various tools like over 19 vaccines etc. 


In Industry

  • To get a useful protein, the transformation of the genetic material of specific cells in an organism by replacing or inserting a gene. 
  • Medicines and doses like human growth hormone., insulin and the development of life-saving vaccines.
  • Development of Supplements such as tryptophan that are useful in the food industry like in cheese-making chymosin
  • Greener fuels can be produced using genetic engineering processes.


In Agriculture

  • Genetic Engineering has its applications in agriculture to fulfil the food needs of the rapidly growing population and demand. Some genetically modified crops have been developed to get more yield from the same land. Like genetically modified wheat and rice which have more nutritional value and yield to aid in malnutrition and hidden hunger. 
  • Development of crops that can tolerate environmental stress like drought, cold and heat without affecting the production. 
  • To lessen the dependence on the chemical pesticides genetically modified crops like Bt Cotton, Bt brinjal and GM Mustard have been developed that have natural pest-killing abilities. 
  • To decrease dependence on chemical fertilizers that badly impact the soil composition, GM crops are developed which have more nutritional value naturally. 


Advantages and Disadvantages of Genetic Engineering

Here are some advantages and disadvantages of Genetic Engineering in the following table:


Advantages Disadvantages
GM crops help produce more food. GM species can disrupt ecosystems by outcompeting others.
GM crops are more resistant to pests and weather. Genetic changes may lead to more defects.
Genetic engineering improves medical treatments. GM organisms might become stronger against diseases.
New types of food with desired traits are created. Ethical concerns arise, like animal welfare.
Faster growth for plants and animals is possible. Eating GM food may lead to health problems like allergies.


Regulation Ethical and Societal Implications in India

Under the Ministry of Environment, Forest and Climate Change the genetic engineering appraisal committee is the main regulatory body for biotechnology in India. It is a statutory body which was established under the provisions of the Environment Protection Act of 1986. The recombinant DNA advisory committee also reviews any development in the field of biotechnology on the international and national levels. One another community that also reviews and monitors the safety of ongoing activity that and walls genetically modified organisms and other research projects is the Review Committee on Genetic Manipulation.  


  • If someone or some organization wants to conduct trials, experiment and release a genetically modified product they have to get permission from the Genetic Engineering of Brazil committee. Which comes under the rules of manufacture use exporter storage of hazardous microorganisms of cells, the GM rule of 1993. 
  • GM rules are applied to every category of microorganism including bacteria viruses fungi mycoplasma algae nematodes protons etc.
  • These rules are applicable to gene technology genetic engineering and upcoming new gene technologies. 


Real-World Successful Examples of Genetic Engineering


Bananas are a means of energy among the fruits. Uganda scientists have successfully made a genetically modified variety of banana in which they inserted a pepper gene. This gene made the new variety resistant to multiple new diseases. 


Abiotic Stress

In the paper industry Frost resistant eucalyptus trees are being introduced thanks to genetic engineering techniques. A variety of rice is made which is the first drought-resistant variety of rice also adapted to the flooded fields. Some crop varieties are developed which can grow in the soil holding smaller quantities of phosphorus and nitrogen. 


Golden Rice

In 2000 a special rice variety was introduced which contains vitamin A. In many poor countries deficiency of vitamin A is the major reason for blindness among children. Also, a variety of rice was produced in 2011 which has four times as much iron in comparison to the regular rice variety. 



In New Zealand, a special variety of onion was introduced which does not make you cry while cutting. After inserting a gene which inhibits the activity of onion enzymes that make people cry. 


Purple Tomatoes

A gene was transferred from a decorative plant into tomato which made the color of tomato purple. This gene helps in the production of the pigment anthocyanin that is responsible for the purple colour of a tomato. It was tested that this tomato variety can prevent cancer.



A gene CAX1 was transferred from the mouse ear cress into carrots to make carrots rich in calcium. These carrots can prevent you from getting osteoporosis disease, which is a deficiency disease caused by a deficiency of calcium. 



In the USA a variety of soybean has been developed that contains higher quality soybean oil. These seeds contain high levels of monounsaturated fats and low levels of polyunsaturated fats. This all also has high stability during the baking process. Another variety of soybean oil has been developed which contains Omega-3 fatty acids. 


Bt Cotton 

BT cotton is a genetically modified variety of cotton in which a gene that makes a special killer protein from Bacillus Thuringiensis bacteria was inserted. This cotton variety naturally produces a killer protein that kills the larvae of a lepidopteran that eats its buds which leads to loss in production. 


Arctic Apple 

A group of Canadian scientists created a variety of Apple with the brand name Arctic Apple. These apples do not turn brown after cutting. 



1. What is genetic engineering?
Genetic engineering is a scientific process that involves modifying the genetic material (DNA or RNA) of organisms to achieve desirable traits such as disease resistance or increased productivity.

2. What are genetically modified organisms (GMOs)?
GMOs are organisms that have had their genetic material altered using genetic engineering techniques, resulting in new traits such as improved resistance to pests or environmental stressors.

3. What are some common applications of genetic engineering?
Genetic engineering is used in medicine to produce drugs such as insulin, in agriculture to create pest-resistant crops, and in industry to produce biofuels and other products.

4. What are some ethical concerns associated with genetic engineering?
Ethical concerns include the potential impact on ecosystems, unintended genetic changes, and questions about the long-term effects of consuming GMOs. There are also concerns about animal welfare and human rights in genetic research.

5. How is CRISPR used in genetic engineering?
CRISPR is a powerful genome-editing tool that allows scientists to precisely target and modify specific genes within an organism’s DNA, enabling the correction of genetic disorders and other applications.

6. What is recombinant DNA technology?
Recombinant DNA technology involves combining DNA from different sources to create new genetic material, which is then introduced into a host organism to express a desired trait.

7. What are some examples of genetically engineered crops?
Examples of genetically engineered crops include Bt cotton, which produces a protein toxic to certain pests, and golden rice, which contains added vitamin A for improved nutrition.

8. What are some safety measures in genetic engineering research?
Safety measures include regulatory oversight, ethical review boards, and adherence to guidelines for containment and testing to minimize potential risks to human health and the environment.

9. How can genetic engineering benefit medicine?
Genetic engineering benefits medicine by enabling the production of drugs such as insulin, vaccines, and gene therapies, as well as the development of diagnostic tools and personalized treatments.

10. What is the future of genetic engineering?
The future of genetic engineering includes advancements in gene therapy, precision medicine, and sustainable agriculture. Researchers are exploring new ways to address challenges such as disease, hunger, and environmental sustainability.

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