• Cloning is a technique scientists use to make exact genetic copies of living things. Genes, cells, tissues, and even whole animals can all be cloned.
  • The copied material, which has the same genetic makeup as the original, is referred to as a clone.
  • Production of cells or organisms originally derived from a single original cell or organism by the asexual method under laboratory conditions.
  • Dolly was the first mammal successfully cloned. The first clones were frogs.
  • Scientists at India’s National dairy research institute Karnal Haryana produced the first cloned buffalo in 2009; however, the buffalo died a few days later.
CLONING

Types of Cloning

There are three different types of cloning:

  • Gene cloning, which creates copies of genes or segments of DNA.
  • Reproductive cloning, which creates copies of whole animals.
    • In this we actually reproduce not organ but entire being(donor) from where we got genetic information.
    • Egg cell is placed into the uterus after few divisions in it. The cell is allowed to develop into foetus that is genetically identical to the donor of the original nucleus.
  • Therapeutic cloning, which creates embryonic stem cells. Researchers hope to use these cells to grow healthy tissue to replace injured or diseased tissues in the human body.
    • In therapeutic cloning, the aim is to clone cells that make particular organs or types of tissue.
    • Egg is placed in a Petri dish to develop into embryonic stem cells which have shown potential for treating several ailments.
    • It is also called somatic cell nuclear transfer or research cloning.
    • In this technique, the resultant embryo is allowed to grow for 14 days.
    • Its stem cells would then develop into human tissue or a complete human organ for transplant.
    • Use of therapeutic cloning:
      • Overcomes the problem of immune rejection which is a major concern in tissue transplantation
      • Cell which are removed can give rise to all cells in the body except embryo i.e. it can treat diseases by replacing damaged cells
      • Help in studying stem cells and future medical importance of it to treat against common diseases affecting today such as diabetes and Parkinson’s disease.
      • Understanding the process of cancer formation
      • Help in plastic, reconstructive and cosmetic surgery.

Human Cloning

  • Positive
    • Can solve the issue of infertility
    • Can help save a life in case of kidney failure
    • May be possible to reproduce sudden trait in humans via cloning
  • Negative
    • Tamper with genetics in human beings, raises the probability of deliberate reproduction of undesirable traits.
    • May violate social norms
    • Endangers and exploits women: Put them on high risk of ovarian cancer, infertility.

Methods:

  1. Natural: This happens naturally when one embryo spontaneously divides into two or more embryos, thus creating identical twins or, sometimes, triplets or even more
  2. Artificial: An existing embryo is mechanically divided into two or more embryos that are then allowed to develop naturally
  3. Artificial and Donor: Through the use of somatic cell of Donor.

Significance

  • An embryo made by cloning can be turned into a stem cell factory. Stem cells are an early form of cells that can grow into many different types of cells and tissues. Scientists can turn them into nerve cells to fix a damaged spinal cord or insulin-making cells to treat diabetes.
  • The cloning of animals has been used in a number of different applications. Animals have been cloned to have gene mutations that help scientists study diseases that develop in the animals.
  • Livestock like cows and pigs have been cloned to produce more milk or meat.Example India is doing this project on Indigenous breeds
  • Cloning might one day bring back extinct species like the woolly mammoth or giant panda.
  • It overcomes the problem of immune rejection which is major concern during organ transplantation
  • It can help in understanding process of ageing

Issues

  • Many researchers think it is worthwhile to explore the use of embryonic stem cells as a path for treating human diseases. However, some experts are concerned about the striking similarities between stem cells and cancer cells. Both cell types have the ability to proliferate indefinitely and some studies show that after 60 cycles of cell division, stem cells can accumulate mutations that could lead to cancer. Therefore, the relationship between stem cells and cancer cells needs to be more clearly understood if stem cells are to be used to treat human disease.
  • Researchers have observed some adverse health effects in sheep and other mammals that have been cloned. These include an increase in birth size and a variety of defects in vital organs, such as the liver, brain and heart.
  • Another potential problem centers on the relative age of the cloned cell’s chromosomes. As cells go through their normal rounds of division, the tips of the chromosomes, called telomeres, shrink. Over time, the telomeres become so short that the cell can no longer divide and, consequently, the cell dies. This is part of the natural aging process that seems to happen in all cell types. As a consequence, clones created from a cell taken from an adult might have chromosomes that are already shorter than normal, which may condemn the clones’ cells to a shorter life span. Indeed, Dolly, who was cloned from the cell of a 6-year-old sheep, had chromosomes that were shorter than those of other sheep her age. Dolly died when she was six years old, about half the average sheep’s 12-year lifespan.
  • Reproductive cloning would present the potential of creating a human that is genetically identical to another person who has previously existed or who still exists. This may conflict with long-standing religious and societal values about human dignity, possibly infringing upon principles of individual freedom, identity and autonomy. However, some argue that reproductive cloning could help sterile couples fulfill their dream of parenthood. Others see human cloning as a way to avoid passing on a deleterious gene that runs in the family without having to undergo embryo screening or embryo selection.
  • Therapeutic cloning, while offering the potential for treating humans suffering from disease or injury, would require the destruction of human embryos in the test tube. Consequently, opponents argue that using this technique to collect embryonic stem cells is wrong, regardless of whether such cells are used to benefit sick or injured people.

India does not have specific laws regarding cloning but has guidelines prohibiting whole human cloning or reproductive cloning. India allows therapeutic cloning and the use of embryonic stem cells for research purposes


Restriction Fragment Length Polymorphism (RFLP)

  • Restriction Fragment Length Polymorphism is a technique that uses Restriction enzymes to identify variations in the homologous DNA sequences.
  • The DNA isolated from an individual organism has a unique sequence and even the members within a species differ in some parts of their sequence.
  • The restriction sites would also vary and hence if DNA from a given individual was subjected to digestion with a restriction enzyme the fragments generated would vary when compared with another individual’s DNA similarly digested.
  • A major application of this technique is DNA Fingerprinting.
  • Individuals except identical twins vary in their RFLP pattern as indicated schematically in the agarose gel electrophoresis.
  • Hence the term DNA fingerprint is used and this is the basis of a major technique used in forensic science to identify and relate individuals.
RESTRICTION FRAGMENT LENGTH POLYMORPHISM (RFLP)

GMO (Genetically Modified Crops)

  • According to WHO, Genetically modified organisms are organisms in which genetic material has been altered in a way that does not occur in natural recombination.
  • All GM crops in India require approval from the Genetic Engineering Appraisal Committee (GEAC) for use in commercial production.
  • Globally GM crops were commercially introduced in 1996. Crops such as corn, cotton, and soybean have been engineered to resist insect pests and herbicides and are now planted widely in many parts of the world.
    • USA, Brazil, Argentina, India, and Canada are top GM crops growing countries, together accounting for approx. 90% area of the GM cultivation.
  • BT cotton is the only genetically modified crop allowed in India. Biotech regulator recently allowed for the commercial production of GM Mustard in the country. Several groups opposed the GEAC’s decision.
    • GEAC has allowed biosafety research field trials of two new transgenic varieties of indigenously developed Bt Brinjal – namely Janak and BSS-793, containing the Bt Cry1Fa1 gene (Event 142) – in eight states during 2020-23 only after taking no-objection certificate (NOC) from states concerned and confirmation of the availability of isolated stretch of land for this purpose.
      • These indigenous transgenic varieties of are developed by the National Institute for Plant Biotechnology, (NIPB, erstwhile National Research Centre on Plant Biotechnology, New Delhi), Indian Council of Agricultural Research (ICAR).
  • Genetically modified crops (GM crops) are plants used in agriculture, the DNA of which has been modified using genetic engineering methods.
  • Plants, bacteria, fungi, and animals whose genes have been altered by manipulation are called Genetically Modified Organisms (GMO).
  • GM plants have been useful in many ways. Genetic modification has:
    • enhanced nutritional value of food, e.g., Vitamin ‘A’ enriched rice.
    • made crops more tolerant to abiotic stresses (cold, drought, salt, heat).
    • reduced reliance on chemical pesticides (pest-resistant crops).
    • helped to reduce post-harvest losses.
    • increased efficiency of mineral usage by plants (this prevents early exhaustion of fertility of soil).
  • In addition to these uses, GM has been used to create tailor-made plants to supply alternative resources to industries, in the form of starches, fuels and pharmaceuticals.
GENETICALLY MODIFIED CROPS
GM crops Benefits
BT Crops
  • BT stands for Bacillus thuringiensis.
  • Bacillus thuringiensis is a gram-positive, spore-forming bacterium which is mainly found in the soil and hence it is also known as a soil-dwelling bacterium.
  • This bacterium produces a protein that acts as a toxin for those insects destroying the yield. This bacterium is mainly used in the sprays for commercial agriculture and for organic farming.
  • The use of this spray on crops is safe for the environment and causes no harm to the consumers.
  • The practice of using BT started in the year 1996 and began with using small quantities of genes from BT. With the help of this genetic transformation, plants used to create the necessary proteins to protect the crop from pests.
  • All over the globe, in a land spanning 29 million acres, BT corn, BT potato, and BT cotton were grown in the year 1999. Relying on this technology alone, approximately 92 million dollars was saved by the United States.
  • How does the cry protein work?
    • When an insect feeds on the plants, the cry protein present in the plants crystallizes the digestive system of insects and it starves to death since the cry protein is toxic to the organism’s digestive tract. Remember that it affects the insect’s digestive system and has no effect on the human digestive system.

Advantages of BT Crops.

  • They help in controlling soil pollution as the use of synthetic pesticides are reduced when the plants begin to produce the toxins by themselves in their own tissues.
  • BT Crops help in protecting the beneficial insects.
  • Reduced manpower and labour charges.
  • The pests hiding inside plant parts are controlled effectively.
  • It is cost-effective as multiple sprays are not needed.

Disadvantages of BT Crops

  • The BT crops are more costly than the normally grown crops.
  • There is a possibility for allergic reactions while using these crops.
  • BT Crops are not effective for certain pests including spider mites, seed corn.
Regulatory Procedures involved in the development and approval of GM crops in India
  • The rules governing the handling of GMOs and products thereof were notified in 1989 under Environment Protection Act 1986 and guidelines were issued later.
    • There is a well-established regulatory framework for approval of GM Crops as per “Rules for the Manufacture/Use/Import/Export and Storage of Hazardous Microorganisms, Genetically Engineered Organisms or Cells, 1989” under the Environment (Protection) Act, 1986.
  • Two government agencies, MoEFCC and the Department of Biotechnology (DBT) are responsible for the implementation of the regulations.
  • There are various authorities to handle different aspects of the regulation.
    • These are the Recombinant DNA Advisory Committee, Institutional Bio-Safety Committee, Review Committee on Genetic Manipulation, GEAC, State Biotechnology Coordination Committee, and District level Committee.
  • A series of guidelines for safety assessment procedures to be followed at various stages of the development of GMOs have been adopted from time to time.
  • GEAC is the apex body that allows for the commercial release of GM crops.
  • GEAC shall have powers to revoke approvals in case of:
    • Any new information on the harmful effects of GMOs.
    • GMOs cause such damage to the environment as could not be envisaged when approval was given.
    • Non-compliance with any conditions stipulated by GEAC.
Genetic Engineering Appraisal Committee (GEAC)
  • The top biotech regulator in India is Genetic Engineering Appraisal Committee (GEAC).
  • The committee functions as a statutory body under the Environment Protection Act 1986 of the Ministry of Environment & Forests (MoEF).
  • It was earlier known as Genetic Engineering Approval Committee. Under the EPA 1986 Rules for Manufacture, Use, Import, Export, and Storage of Hazardous Microorganisms/Genetically Engineered Organisms or Cells, GEAC is responsible for granting permits to conduct experimental and large-scale open field trials and also grant approval for commercial release of biotech crops.

Polymerase Chain Reaction

  • The polymerase chain reaction or PCR as it is commonly known was invented by Kerry Mullis in 1985.
  • It results in the selective amplification of a specific region of a DNA molecule and so can also be used to generate a DNA fragment for cloning.
  • The basic principle underlying this technique is that when a double-stranded DNA molecule is heated to a high temperature, the two DNA strands separate giving rise to single-stranded molecules which can be made to hybridise with small oligonucleotide primers (single-stranded) by bringing down the temperature.
  • If to this an enzyme called DNA polymerase and nucleotide triphosphates are added, much like what happens during replication, i.e primer extension occurs.
  • This procedure is repeated several times ultimately results in amplification of the DNA stretch between the two primers (one on each strand of the DNA).
  • A single PCR amplification cycle involves three basic steps of denaturation, annealing, and extension.
  • In the denaturing step, the target DNA is heated to a high temperature, above 80 C which results in DNA strand separation.
  • PCR-based diagnosis is faster, safer, and more specific – because it does not use live pathogens; instead, DNA from the infected tissue is isolated and the PCR technique is carried out using primers having specific complementary sequences to the pathogen DNA.
  • It is interesting that archaeologists are using combinations of PCR and fingerprinting analysis to relate and establish ancient Egyptian dynasties from samples obtained from mummies.

Molecular farming

  • Molecular farming is a new technology that uses plants to produce large quantities of pharmaceutical substances such as vaccines and antibodies. It relies on the same method used to produce genetically modified (GM) crops – the artificial introduction of genes into plants.
  • A number of vaccines, antibodies, and other therapeutic substances made in plants such as tobacco, maize, potato, and carrot are already commercially available or in advanced clinical trials. Producing pharmaceuticals in plants is easy and efficient compared to conventional production methods.
  • Typically, animal or microbial cell cultures are used to produce vaccines but costs associated with maintenance, safety; storage and transport are 80% higher compared to plant-derived vaccines.

Edible Vaccines

  • A genetically manipulated food containing organisms or related antigens that may provide active immunity against infection.
  • Edible vaccines against many microorganisms are being developed, with the goal of using them to vaccinate children in nonindustrialized countries where there are obstacles to the use of the traditional injectable vaccine.
  • Examples of Edible vaccines: Transgenic Potatoes for Diarrhoea:
    • They were tested and found to be effective, however raw potatoes are non-edible and cooking destroys protein antigens.
EDIBLE VACCINES

Advantages of Edible vaccines

  • They are cheap therefore they can be mass-produced.
  • They are stable at room temperatures.
  • Need to process and purify do not occur
  • Most importantly they trigger immunity at the mucosal surface. For e.g.: Those that line the mouth.

Disadvantages of edible vaccines

  • Will the antigen be able to survive the hostile condition of the stomach and even if they will then be trigger immune system in the right way.
  • Continued vaccine production might not be guaranteed due to changes in plants
  • Glycosylation in patterns in plants differ from humans and could affect the functionality of vaccine.

Three Parent Baby / Mitochondrial Gene Therapy

  • A team of Greek and Spanish doctors has produced a baby (in Greece) using genetic material from two women and a man.
    • The procedure replaces a small amount of faulty DNA in a mother’s egg with healthy DNA from a second woman, so that the baby would inherit genes from two mothers and one father. The idea is to prevent certain genetic diseases being passed on to children.
  • The technique used is called as ‘Maternal Spindle transfer’ in which maternal DNA is put into the egg of a donor woman, which is then fertilized using the father’s sperm.
  • The procedure was developed to help existing IVF treatments in which mothers have mitochondrial diseases.
  • The technique is considered controversial by some doctors.
  • Mitochondrial diseases are long-term, genetic, often inherited disorders that occur when mitochondria fail to produce enough energy for the body to function properly.
  • In Vitro Fertilization (IVF) is a medical procedure in which mature egg cells are removed from a woman, fertilized with male sperm outside the body, and inserted into the uterus of the same or another woman for normal gestation.
  • Britain became the first country to allow for a three-parent baby and in 2017 the first 3 parent baby was born.
THREE PARENT BABY

Risks:

  • Several people argue that this leads to designer babies
  • Experts have warned that three-parent babies could be at greater risk of cancer and premature ageing, and would need to be monitored all their lives.
  • Since this is uncharted territory and the children born from this technology would have heritable genetic changes, there are also significant unknown risks to future generations.
  • There are numerous serious risks associated with this technology. These include most notably the possibility that developmentally disabled or deceased babies will be produced.
  • Aberrations could also lead to developmental defects in babies or also manifest in later life as increased rates of ageing of cancer.

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