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What is Gene Editing, CRISPR/Cas9, Examples and Benefits?

Genome editing is also known as gene editing. Various approaches to genome editing have been developed. How is it done, what are its applications, benefits, examples, etc? Let us find out!
Oct 15, 2020 19:35 IST
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Gene Editing
Gene Editing

As we know the 2020 Nobel Prize in Chemistry was announced on 7 October, 2020. It was awarded jointly to Emmanuelle Charpentier and Jennifer A. Doudna "for the development of a method for genome editing." This has revolutionized the molecular life sciences.

But do you know what is gene editing or genome editing?

Genome Editing/Gene Editing

It is a method by which scientists change the DNA of several organisms, including plants, bacteria, and animals. Editing in DNA results in the changes in physical traits such as eye colour and disease risk. Different technologies are used by scientists to do this.

Such technologies act like scissors which help in cutting the DNA at a specific spot. After this, scientists can remove, add, or replace the DNA where it was cut.

Background

In the late 1900s, the first genome editing technologies were developed. In 2009, a new genome-editing tool known as CRISPR was invented. It has made it easier than ever to edit DNA. The editing tool CRISPR is simple, faster, cheaper, and more accurate than older genome editing methods. Various scientists who perform genome editing are now use CRISPR.

For what genome editing technology is used? Or uses of genome editing technology

In various ways, scientists use genome editing and one way is to investigate different diseases that affect humans. Scientists edit the genome of animals like mice and zebrafish because animals contain many of the same genes as humans. For example, mice and humans share about 85% of their genes. By making changes or changing a single gene or multiple genes in a mouse, scientists would come to know how these changes affect the health of the mouse and can predict how similar changes in human genomes might affect human health.

At the National Human Genome Research Institute (NHGRI), scientists are doing just this. In the Burgess lab for example scientists are studying zebrafish genomes. In the lab, they delete different genes in zebrafish one at a time by using the CRISPR to see how the deletion impacts to fish. On 50 zebrafish genes, the Burgess lab focuses. These genes are similar to the genes in humans that cause deafness. With this, they will be able to understand better the genomic basis of deafness.

Nobel Prize 2020 in Chemistry: All you need to know

Scientists are also developing gene therapies for the treatments involving genome editing to prevent and treat diseases in humans.

It is said that genome editing tools have the potential to help in the treatment of diseases with genomic basis like cystic fibrosis and diabetes. There are two different categories of gene therapies namely germline therapy and somatic therapy.

In Germline therapies, scientists change DNA in reproductive cells like sperm and eggs. In reproductive cells, changes to the DNA are passed down from generation to generation. 

In Somatic therapies, scientists target non-reproductive cells, and changes made in these cells affect only the person who receives the gene therapy.

Scientists successfully used somatic gene therapy in 2015 when one-year-old in the United Kingdom received a gene-editing treatment to help her to fight with leukemia which is a type of cancer. Scientists did not use CRISPR here and instead of it, they used another genome editing technology known as TALENS

Doctors tried various treatments but none of them worked so scientists received special permission to treat the infant using gene therapy. 

This treatment or therapy saved the life of the infant. However, the treatment that was given to the infant is still experimental because the scientific community and policymakers still have to address technical barriers and ethical surrounding genome editing.

What are the technical barriers?

Even though CRISPR improved upon older genome editing technologies but yet it is not perfect. For example, sometimes genome editing tools cut within the wrong spot. Here, scientists are not sure about these errors that how it might affect patients. Therefore, assessing the safety of gene therapies and improving genome editing technologies are critical steps to make sure or ensure that this technology is ready for the patients to use. 

Ethical concerns regarding genome editing

Various ethical concerns can emerge with genome editing including safety. First and foremost is that genome editing should be safe before it is used for treating the patients. 

Some questions that scientists and society must consider are as follows:

1. On an embryo, is it ok to use gene therapy when it is impossible to get permission from the embryo for treatment. Is getting permission from the parents enough?
2. Gene therapies are too expensive and only wealthy people can access and afford them? What will happen? This would worsen the existing health inequalities between the rich and the poor.
3. Is some people use genome editing for traits and not important for health, such as athletic ability or height? Is that okay?
4. Should scientists ever be able to edit germline cells? Edits in the germline would be passed down through generations.

Various countries and organisations have strict regulations to prevent germline editing and the NIH, for example, does not provide funds for research to edit human embryos. At the International Summit on Human Gene Editing, scientists across the world discussed these and similar ethical issues.

2020 Nobel Prize in Chemistry

Emmanuelle Charpentier and Jennifer A. Doudna have discovered one of gene technology’s sharpest tools namely the CRISPR/Cas9 genetic scissors. 

With the help of this technology, researchers can change the DNA of animals, plants, and microorganisms with extremely high precision. It is said that this technology has had a revolutionary impact on the life sciences, it can help in contributing to new cancer therapy and may make the dream of curing inherited diseases come true.

According to Claes Gustafsson, chair of the Nobel Committee for Chemistry "There is enormous power in this genetic tool, which affects us all. It has not only revolutionised basic science but also resulted in innovative crops and will lead to ground-breaking new medical treatments."

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