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Gene Editing

Gene Editing

What is a Gene?

  • Genes contain the bio-information that defines any individual.
  • Physical attributes like height, skin or hair colour, more subtle features and even behavioural traits can be attributed to information encoded in the genetic material.
  • An ability to alter this information gives scientists the power to control some of these features.

What is Genome Editing?

  • Genome editing is a way of making specific changes to the DNA of a cell or organism. An enzyme cuts the DNA at a specific sequence, and when this is repaired by the cell a change or ‘edit’ is made to the sequence.
  • Genome editing (also called gene editing) is a group of technologies that give scientists the ability to change an organism’s DNA. These technologies allow genetic material to be added, removed, or altered at particular locations in the genome.

Background | Gene Editing

  • He Jiankui Chinese researcher shocked the scientific community in 2018 after announcing he had
    successfully altered the genes of twin girls born in November to prevent them from contracting HIV.
  • He had “privately” organised a project team that included foreign staff and used “technology of
    uncertain safety and effectiveness” for illegal human embryo gene-editing, investigators said.
  • But such gene-editing work is banned in most countries, including China.

Cutting-and-pasting DNA (CRISPR-CAS9)

  • It is a unique technology that enables geneticists and medical researchers to edit parts of the genome by removing, adding or altering sections of the DNA sequence.
  • CRISPRs are specialized stretches of DNA. The protein Cas9 (or “CRISPR-associated”) is an enzyme that acts like a pair of molecular scissors, capable of cutting strands of DNA. It allows researchers to easily alter DNA sequences and modify gene function.
  • It is the simplest yet powerful tool for editing genomes and also termed as the most versatile and precise method of genetic manipulation.

 

How does CRISPR – Cas9 work?

  • CRISPR scans the genome looking for the right location and then uses the Cas9 protein as molecular scissors to snip through the DNA.
  • Cas9 endonuclease – guide RNAs to direct it to a particular sequence to be edited. The genetic sequence of the RNA matches the target sequence of the DNA that has to be edited.
  • When Cas9 cuts the target sequence, the cell repairs the damage by replacing the original sequence with an altered version.
  • Unlike other gene-editing methods, it is cheap, quick, easy, safer and more accurate to use because it relies on RNA–DNA base pairing, rather than the engineering of proteins that bind particular DNA sequences.

 

Role of CCR5 Gene in Human body

  • It helps to protect the lungs, the liver and the brain during certain serious infections and chronic diseases.
  • It is known to prompt the immune system to fight the influenza virus in the lungs.
  • In the case of people with multiple sclerosis (disabling of the brain and spinal cord), absence of this gene makes them twice as likely to die early.
  • The CCR5 gene’s protective role against the West Nile virus is also well established.

Can disabling the CCR5 gene prevent HIV?

  • While it is generally believed that babies without a CCR5 gene will become resistant to HIV infection, certain other strains of HIV use another protein (CXCR4) to infect cells and make a person HIV positive.
  • Hence, even people who are born with the ‘non-functional’ CCR5 gene are not completely protected or resistant against HIV infection.
  • Potential Application of Gene Editing
  • Prevention of inherent disease to flow to the offspring. Diabetes and cystic fibrosis can also be eliminated.
  • Extension of the human lifespan by reversing most basic reasons for the body’s natural decline on a cellular level.
  • Designing foods that can withstand harsh temperatures and that are packed full of all the right nutrients.
  • Industrial biotechnology uses such as developing ‘third generation’ biofuels and producing chemicals, materials and pharmaceuticals.
  • Preventing the inheritance of a disease trait as well as speed up the drug discovery process.
  • Counteract the release of a harmful substance to a population by military means.
  • Elimination of predators and pests to help to restore threatened native species of animals and plants.

Advantages of Gene editing

  • CRISPR could be used to modify disease-causing genes in embryos brought to term, removing the faulty script from the genetic code of that person’s future descendants as well.
  • Genome editing (Gene editing) could potentially decrease, or even eliminate, the incidence of many serious genetic diseases, reducing human suffering worldwide.
  • It might also be possible to install genes that offer lifelong protection against infection.

Pros and Cons of CRISPR Technology

Issues with Gene editing

  • Making irreversible changes to every cell in the bodies of future children and all their descendants would constitute extraordinarily risky human experimentation.
  • There are issues including off-target mutations (unintentional edits to the genome), persistent editing effects, genetic mechanisms in embryonic and fetal development, and longer-term health and safety consequences.
  • Some argue that we do not understand the operations of the genome enough to make long-lasting changes to it. Altering one gene could have unforeseen and widespread effects on other parts of the genome, which would then be passed down to future generations.
  • Many consider genome alterations to be unethical, advocating that we should let nature run its course.
  • Few argue that after permitting human germline gene editing for any reason would likely lead to its ignorance of the regulatory limits, to the emergence of a market-based eugenics that would exacerbate already existing discrimination, inequality, and conflict.
  • It will become a tool for selecting desired characteristics such as intelligence and attractiveness.

Gene Editing laws around the world

  • In Russia, the germline gene modification for reproduction is not considered” by the relevant legislation.
  • In Canada and many European countries, the bans are quite strict; in Austria, for example, any intervention involving the human germline is prohibited.
  • In 2018, Japan, sets specific guidelines for the use of CRISPR technology to move towards furthering research on gene-editing in early human embryo development
  • China, India, Ireland, and Japan also have guidelines that are not legally binding. However, those countries, including US, might permit it once such techniques become safer.
  • The European Court of Justice has ruled that organisms altered using gene editing tools should be subjected to the same rules as genetically modified organisms (GMO).

Regulation of Genetically modified organism (GMO) Technologies in India

  • In India, Ministry of Environment, Forest and Climate Change (MoEFCC) introduced the Environment (Protection) Act, 1986 as an umbrella legislation to provide a holistic framework for the protection and improvement to the environment.
  • Thereafter, a series of Rules were notified to address various problems such as hazardous chemicals, hazardous wastes, solid wastes, biomedical wastes, etc.
  • In connection with the application of gene technology, the MoEFCC notified the “Rules for manufacture, use/import/export & storage of hazardous microorganisms/genetically engineered organisms or cells, 1989” as per powers conferred by Sections “Regulation of Genome Engineering Technologies in India”, of Environment (Protection) Act, 1986.
  • These rules are very broad in scope essentially covering entire spectrum of activities involving GMOs and products thereof. New gene technologies apart from genetic engineering have also been included.
  • In 2014, department of biotechnology (DBT) has constituted a dedicated Task Force on “Genome Engineering Technologies and their Applications” with a vision to foster innovation and promote development of Genome-wide Analysis and Engineering Technologies

Concerns regarding Gene editing technology in India

  • Indian protocols prohibit human germ line editing and reproductive cloning, as detailed in the National Guidelines for Stem Cell Research by the Indian Council of Medical Research.
  • However, these guidelines have not yet been converted into specific laws.
  • Past developments in genetic technology have been mishandled, demonstrating the capacity of India’s regulatory organisations. For example, While the permissibility of genetically modified crops (GMO) was still being debated in parliament, they were being illegally and sown in Gujarat in spades because of their perceived profitability.
  • Moreover, the extensive growth of black markets for human organs and counterfeit medicine in India raises several concerns when considering the regulation of profitable gene-editing technology.
  • The potential for misuse in an Indian context is driven by a number of sociocultural factors intrinsic to the subcontinent such as fair skin in Indian society. The question rises is that to what extent will these preferences take form in healthcare markets if consumers are able to manipulate such characteristics through gene editing?

Conclusion | Gene Editing

  • Concerns about Gene editing should be managed through policy and regulation.
  • Years of research is needed to find the long term effect of gene editing
  • A precautionary approach may be favoured as the possible consequences of gene editing may lead to serious and irreversible harm.
  • India should create its own framework for regulating genetically edited organisms instead of following either the European or American models.
  • One should also ask to what degree they are willing to allocate resources towards the development and application of technologies like CRISPR.

 

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SCIENCE AND TECHNOLOGY

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