Genome Editing



Genome editing, also known as genome engineering or gene editing, is a sort of genetic engineering that involves inserting, deleting, modifying, or replacing DNA in a living organism’s genome.

Genome Editing  Techniques:

The core technologies now most used to facilitate genome editing, are

●Clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein 9 (Cas9): CRISPR is the DNA-targeting component of the system, and it is made up of an RNA molecule, or ‘guide’, that is engineered to attach to certain DNA bases via complementary base-pairing.

●CRISPR-associated protein 9 (Cas9) is the nuclease component that cuts the DNA.

●The CRISPR-Cas9 genetic scissors were discovered by Emmanuelle Charpentier and Jennifer A. Doudna, who won the Nobel Prize in Chemistry in 2020.

● Potential loss to diversity : Diversity in all species of animals is a key to evolution on earth. Genetically engineering our species will have a detrimental effect on genetic diversity.

● No Guarantee  of Food Security: 
In India, there is a moratorium on Bt brinjal because there is no scientific consensus on its safety and efficacy.

Three parent Baby 

Techniques to create ‘three-parent babies’ seek to offer mothers a way to have a child without passing on metabolic diseases caused by faulty mitochondria.

Researchers do this by exchanging the diseased mitochondria of a prospective mother with those of a healthy, unrelated donor: the ‘third parent.’

In addition to DNA in the nucleus, some DNA is also present in the mitochondria.

●This technology uses the technique of Pronuclear Transfer.

In pronuclear transfer, a zygote is created by first fertilizing the mother’s egg with the father’s sperm.

☆The donor egg is then fertilized and has had its own nucleus removed before the pronuclei of the egg and sperm are removed from the zygote and put into the donor egg (a pronucleus is the nucleus of the egg or sperm at the stage of fertilization prior to nuclear fusion).

☆The donor egg’s zygote is subsequently inserted into the mother’s uterus.

☆During fertilization the nuclear DNA is formed with 46 chromosomes (i.e., 23 from mother & 23 chromosomes from the father).

☆The Mitochondrial DNA has only one chromosome and it codes for only specific proteins responsible for metabolism

☆Mitochondrial DNA is inherited only from the mother & thus it is more effective to trace human ancestry.

1).In the context of recent advances in human reproductive technology, ‘Pronuclear Transfer” is used for (2020)

(a)Fertilization of egg in vitro by the donor sperm

(b)Genetic modification of sperm producing cells.

(c)Development of stem cells into functional embryos

(d)Prevention of mitochondrial diseases in offspring.

Somatic cell Nuclear Transfer:

1): Somatic Cell nuclear Transfer  (SCNT) technique  in which the nucleus of the somatic ( body) cell is transferred to the cytoplasm of an enumerated egg ( an egg that has had it's own nucleus removed ).Once inside the egg, the somatic nucleus is  reprogrammed by egg cytoplasmic factors to become a zygote ( fertilized eggz) nucleus.

2)The egg is allowed to develop to the blastocyst stage, at which point a culture of embryonic stem cells (ESCs) can be created from the inner cell mass of the blastocyst.

For example, Cloning of Dolly Sheep

1).Dolly was cloned from a cell taken from the mammary gland of a six-year-old Finn Dorset sheep and an egg cell taken from a Scottish Blackface sheep.

2).She was born to her Scottish Blackface surrogate mother on 5th July 1996.

3)Dolly’s white face was one of the first signs that she was a clone because if she was genetically related to her surrogate mother, she would have had a black face.

4Dolly’s DNA came from a mammary gland cell, and she was named after the country singer Dolly Parton.

1.What is the application of Somatic Cell Nuclear Transfer Technology? (2017)
    (a)Production of bio larvicides
      (b)Manufacture of biodegradable plastics
        (c)Reproductive cloning of animals
          (d)Production of organisms free of diseases

          Genetically Engineered Insulin

          Insulin used for diabetes was earlier extracted from pancreas of slaughtered cattle and pigs.

          1).Insulin from an animal source, though, caused some patients to develop allergy or other types of reactions to the foreign protein.

          2).In 1983, Eli Lilly, an American company prepared two DNA sequences corresponding to A and B, chains of human insulin and introduced them in plasmids of E. coli to produce insulin chains.

          3)Chains A and B were produced separately, extracted, and combined by creating disulphide bonds to form human insulin.

          Gene Therapy

          Gene therapy is a technique for treating genetic problems that includes replacing faulty genes with healthy ones.

          It is a way of introducing DNA into human cells that is done artificially.

          Gene therapy can be divided into two categories.

          Somatic Gene Therapy (SGT)

          This type is most seen in the somatic cells of the human body.

          This is specific to a particular person, and the damaged cells will only be replaced with healthy cells in that person.

          Therapeutic genes are introduced into the somatic cells of the human body using this procedure.

          This approach of gene therapy is thought to be the best and safest.

          Gene Therapy in the Germline

          It happens in the human body’s germline cells.

          Generally, this approach is used to address disease-causing genetic abnormalities that are handed on from parents to their children.

          The procedure entails inserting healthy DNA into the cells that produce reproductive cells, eggs, or sperms.

          Application in Bioenergy

          Biofuels derived from biomass are renewable and sustainable energies with the potential to replace fossil fuels.

          Biotechnology can help to speed up the selection of varieties that are more suited to biofuel production – with increased:

          1) biomass per hectare,

          2) increased content of oils (biodiesel crops) or

          3)fermentable sugars (ethanol crops), or

          4)improved processing characteristics that facilitate their conversion to biofuels.

          Utilization of microbial fuel cells is found to be useful for sustainable bioenergy synthesis via completing the wastewater treatment processes with electric energy synthesis.

          Environmental Biotechnology

          Environmental biotechnology, specifically, refers to the use of procedures to safeguard and restore the environment’s quality.

          Mycorrhizal biotechnology: Mycorrhizae are indigenous to soil and plant rhizosphere and potential tools for sustainable agriculture. They enhance the growth of a root system and even of an entire plant and often control certain plant pathogens.

          1). Numerous studies have documented the fundamental importance of mycorrhizal symbiosis and other microbial systems in reclamation and restoration of contaminated and disturbed ecosystems


          Bioremediation is the process of using microorganisms to remove or detoxify toxins from soils, water, or sediments that would otherwise be harmful to human health.

          ■ Bioremediation is also known by the terms biotreatment, bioreclamation, and biorestoration.

          ■ Microorganisms are employed in sewage treatment plants to remove typical pollutants from wastewater before it is discharged into rivers or the sea.

          ■ Lindane (Hexa-Chlorocyclohexane) bioremediation technology has been developed


          Phytoremediation is a bioremediation process that uses various types of plants to remove, transfer, stabilize, and/ or destroy contaminants in the soil and groundwater.

          ■Phytoremediation treatment processes have been developed for the degradation of dyes from textile industrial effluent.

           ■The study showed that the developed process has the potential for textile dyes and effluentreatment. 

          phyto _ degradation: In this process, plants metabolize and destroy contaminants within plant tissues.


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