Sumera B Reshi
Genomics research is shaping the future of medicine and it has even been called the “discovery of the century.” This technology is known as CRISPR (clustered, regularly interspaced, short palindromic repeat) has emerged with breathtaking speed as a disruptor in the field of life sciences. Genome editing has enhanced our ability to alter DNA.
The technique has recently become much more efficient, faster and cheaper. Gene editing (or genome editing) is the insertion, deletion or replacement of DNA at a specific place in the genome of an organism or cell. It is usually achieved in the lab using engineered nucleases also known as ‘molecular scissors’.
If now humans can alter DNA, would that mean, we can modify any DNA in order to rectify genetic disorders such as sickle cell anemia or hemophilia. And you may also have heard of deliberate genetic enhancement, to realize a healthy person’s dreams of improving their genome. Each day, scientists are trying hard to come to the rescue of the humanity by inventing safest cure and medication to the human population on this blue planet.
Among many technologies, recombinant DNA has arguably been one of the safest. There have been numerous benefits in both medicine and agriculture. For instance, Hepatitis B vaccine or Australian Ian Fraser’s Gardasil vaccine, which protects against cervical cancer viruses is all due to recombinant DNA technology.
The genetic sequences that give CRISPR its name are part of an invulnerable response to bacteria. Scientists have found ways to use the material to subtract or add specific genes to an organism’s genetic code to achieve desired results. Editing DNA can lead to changes in physical traits, like eye color, and disease risk. Scientists use different technologies to do this. These technologies act like scissors, cutting the DNA at a specific spot. Then scientists can remove, add, or replace the DNA where it was cut.
What exactly is Genome Editing?
Since the cell is a basic functional unit of life, cells of all living organism (e.g. a human, animal, plant, bacterium) contain DNA, a type of molecule that is passed from one generation to the next during reproduction and contains a coded message. DNA is involved in many essential biological processes including building cells and controlling their number and type, the production of energy, the regulation of metabolism, and fighting disease.
The term ‘genome’ generally refers to the entire sequence of DNA of an organism. The genome includes genes: arrangement of DNA with specific functions that are involved in the production of the proteins needed to carry out many biological roles. It also includes regions of DNA that promote or inhibit gene activity, and regions that do not appear to affect protein production or function.
Genome editing techniques use certain proteins that can cut DNA in a precise, targeted location. This family of proteins was discovered in the 1960s, it is only since around 2005 that the ability of some of them to make precisely targeted cuts at almost any position in the genome has been recognized and utilized by scientists.
Among the recent genome editing technologies, CRISPR-based methods are particularly promising due to their relative efficiency, low cost; and ease of use, and the prospect of making edits at multiple sites in the genome in a single procedure.
CRISPR-Cas9 is a widely used genome editing method. It has two components. CRISPR stands for ‘clustered regularly interspaced short palindromic repeats’. This refers to the basis of the ‘guide system’ that finds the ‘target’ – the specific sequence of the DNA that is to be modified. Cas9 stands for ‘CRISPR-associated protein 9’, the protein that cuts the DNA at the target site. CRISPR-Cas9 systems that target specific classifications can be produced relatively easily in a laboratory, or obtained in the form of commercially available kits that can be purchased online.
Scientists are working day in & day out to develop gene therapies – treatments involving genome editing – to prevent and treat diseases in humans. Genome editing tools have the potential to help treat diseases with a genomic basis, like cystic fibrosis and diabetes.
In 2015, scientists successfully used somatic gene therapy when a one-year old in the United Kingdom named Layla received a gene editing treatment to help her fight leukemia, a type of cancer. These scientists did not use CRISPR to treat Layla, instead they used another genome editing technology called TALENs.
Gene editing has significant potential to benefit human health. At the same time, it raises profound questions that require public deliberation — what if we make alterations we regret? What if seemingly safe genetic changes prove to have unintended consequences? What are the standards for safety as the medical community seeks to explore these tools in an effort to diminish suffering? Surely, this technology is a blessing for human kind when we have numerous challenges these days due to radiation hazards, climate change, alternations in the ecosystems etc. But we need to prepare ourselves for its downside as well as and nothing is foolproof, not even gadgets, meds or therapies.
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