What is gene editing and how could it shape our future?

THE CONVERSATION 

It is the most exciting time in genetics since the discovery of DNA in 1953. This is mainly due to scientific breakthroughs including the ability to change DNA through a process called gene editing. 

The potential for this technology is astonishing – from treating genetic diseases, modifying food crops to withstanding pesticides or changes in our climate, or even to bring the dodo “back to life”, as one company claims it hopes to do.

We will only be hearing more about gene editing in the future. So if you want to make sure you understand new updates, you first need to get to grips with what gene editing actually is. 

Our DNA is made of four key molecules called bases (A, T, C and G). Sequences of these four bases are grouped into genes. These genes act as the “code” for key substances the body should make, such as proteins. Proteins are important molecules, vital for maintaining a healthy and functional human being. 

Genes can be short, typically made of less than a hundred bases. A good example includes ribosomal genes, which code for different ribosomes, molecules which help create new proteins. 

Long genes are made up of millions of bases. For example, the DMD gene codes for a protein called dystrophin, which supports the structure and strength of muscle cells. DMD has over 2.2 million bases.

How does gene editing work?

Gene editing is a technology that can change DNA sequences at one or more points in the strand. Scientists can remove or change a single base or insert a new gene altogether. Gene editing can literally rewrite DNA. 

There are different ways to edit genes, but the most popular technique uses a technology called CRISPR-Cas9, first documented in a pioneering paperpublished in 2012. Cas9 is an enzyme that acts like a pair of scissors that can cut DNA. 

It is assisted by a strand of RNA (a molecule similar to DNA, in this case created by the scientist), which guides the Cas9 enzyme to the part of the DNA that the scientist wants to change and binds it to the target gene. 

Depending upon what the scientist wants to achieve, they can just remove a segment of the DNA, introduce a single base change (for example changing an A to a G), or insert a larger sequence (such as a new gene). Once the scientist is finished, the natural DNA repair processes take over and glue the cuts back together.

What could gene editing do?

The benefits of gene editing to humanity could be significant. For example, making a single base change in people’s DNA could be a future treatment for sickle cell disease, a genetic blood disease. People with this disease have just one base that has mutated (from A to T). This makes the gene easier to edit compared with more complex genetic conditions such as heart disease or schizophrenia. 

Scientists are also developing new techniques to insert larger segments of bases into the DNA of crops in the hope they can create drought resilient crops and help us adapt to climate change…