Genome editing (also called gene editing) is a group of technologies that give scientists the ability to change an organism’s DNA (Deoxyribonucleic acid).
These technologies allow genetic material to be added, removed, or altered at particular locations in the genome. Several approaches to genome editing have been developed.
There are currently three powerful Gene editing technologies: Zinc-finger nucleases (ZFNs), Transcription activator-like effector nucleases (TALENs) and CRISPR-Case9 Technology.
There are two different types of gene editing technology depending on which types of cells are treated:
Somatic gene therapy: transfer of a section of DNA to any cell of the body that doesn’t produce sperm or eggs. Effects of gene therapy will not be passed onto the patient’s children.
Germline gene therapy: transfer of a section of DNA to cells that produce eggs or sperm. Effects of gene therapy will be passed onto the patient’s children and subsequent generations
How does CRISPR-Cas9 gene works?
It is a Gene editing technique which is short for “Clustered regularly interspaced short palindromic repeats and CRISPR-associated protein 9”
The CRISPR-Cas9 gene editing tool has two components — a short RNA (Ribonucleic acid) sequence that can bind to a specific target of the DNA and the Cas9 enzyme which acts like a molecular scissor to cut the DNA.
To edit a gene of interest, the short RNA sequence (gRNA) that perfectly matches with the DNA sequence that has to be edited is introduced.
Once it binds to the DNA, the Cas9 enzyme cuts the DNA (like scissors) at the targeted location where the RNA sequence is bound. Once the DNA is cut, the natural DNA repair mechanism is utilised to add or remove genetic material or make changes to the DNA.
CRISPR is a key part of the immune system. For instance, when a virus enters bacteria, it fights back by cutting up the virus’s DNA. This kills the virus but bacteria store some of the DNA.
The next time there is an invasion, bacteria produce an enzyme called Cas9 which matches the stored fingerprints with that of the invader’s. If it matches, Cas9 can cut the invading DNA.
How does CRIPSR helps improve immune system?
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.
Moral perspectives on genome editing:
Science as a moral enterprise: This centres on the idea that the freedom granted to scientists and the trust placed in them by the public is implicitly based on the expectation that science will improve the conditions of human existence and of the wider environment.
Intervening in the genome: Few people argue that intervening in the genome is intrinsically more important than other ways of manipulating nature, but most acknowledge that it can have significant adverse implications on future generations.
Moral conservatism: It is often presented as a scepticism about the motives of deliberate human interventions. It may also express concerns that genome editing is moving too quickly for processes of critical reflection (e.g. law, regulation, cultural practices) to keep pace.
Moral norms and human rights: Concerns that certain uses of a technology may interfere with human rights are often invoked as reasons for ruling certain uses of genome editing.
Welfare and risk: The concept of welfare suggests a potentially measurable set of consequences by which to judge and compare different proposed initiatives