An Introduction to Gene Editing.

*extremely basic overview to this emerging technology for those who have never been exposed to it*

Genes carry information that determine your traits as a segment of DNA needed to build and maintain organs and tissues in our bodies. Think about them as a biological template your body uses to make structural protein and enzymes. They have 4 base letters known as A, C, T and G. Genes are stored in chromosomes, which are in the nucleus of the cell. They are so incredibly small because we have 20,000 of them in the nucleus of each cell!

The DNA double helix has 6 billion of these building blocks, and all of the letters are arranged in a specific sequence. If there is an error in the DNA sequence there can be extreme consequences. There are many incurable diseases such as cystic fibrosis, hemophilia, and sickle cell anemia which have originated from a single gene with a mutation.

But what are these letters and what do they mean? Adenine (A), Cytosine ©, Thymine (T), Guanine (G) are all part of the genetic code. The molecules in DNA pair up as such- Adenine pairs with Thymine & Cytosine pairs with Guanine.

Introduction to Gene Editing

Introducing gene editing, what we hope is a solution to all of these incurable diseases. Gene editing is a group of engineering technology allowing scientists to make changes to a specific sequence in the DNA, essentially altering an organism’s DNA. There are 3 types of editing, 1)altering genetic material, 2) removing genetic material, and 3) adding genetic material at certain locations in the genome. The concept of genetic engineering has been in the works since the 1950s. After doing extensive research, half way through the 20th century, a group of scientists learnt that the sequence of DNA bases (ACTG) is passed down from parent to children. Small alterations in the genetic code were molecular mistakes that often distinguished people from being either healthy or diseased. They realized that if they could identify the specific location in the genome where the mutation was located, they could potentially fix the mistakes

How does it work?

Now that you know about genes, and what gene editing is, how does it work? Well, it’s performed using enzymes that are engineered to target a particular sequence and location on the genome. They cut into the DNA strands, and from then existing DNA is able to be removed and inserted as a replacement to the current sequence containing errors.

There are several ways scientists have been able to edit genes, however the key among these technologies has been the molecular tool called Crispr-Cas9. Crispr is a guided molecule that finds the specific location in the genetic code where the mutation or error is. The other part is the Cas9 which is an enzyme that cuts the DNA. Of course there is a much more complex explanation to this science, however this is an introductory article.

This was discovered by the incredible scientists Jennifer Doudna, and Emmanuelle Charpentier. It’s an incredible technology that is allowing researchers to alter DNA, remove and insert it where to cure disease. The problem is the identification of the exact location to make a break in the DNA when there are more than 3 billion base pairs in the human genome. This is not easy.

Another challenge is getting the gene editing molecules to the right cells. With other drugs, it is much easier due to the minuscule size of the molecules. In comparison the gene editing molecules are huge, and therefore face difficulty entering the desired cells. Right now, this is being done by putting harmless viruses into the gene editing molecules. These viruses are directed to certain individual cell types, and after they are in the body, they target those cells and the gene editing molecules are released to make the changes in DNA.

Right now, gene editing doesn’t have to be done in the body. For example, to cure HIV, scientists are actually collecting blood cells, making necessary genetic edits and then infusing the altered cells back into patients.

This is just the beginning of the gene editing revolution. Genetic engineering has many implications for replacing a mutation and curing the patient of a condition. It can also be used to turn off certain genes from being expressed. It can be used to cure cancer, blood disorders, blindness, AIDS, cystic fibrosis, Huntington’s, and so many more. It’s groundbreaking.

So how can we get involved in gene editing? Well, the first step is to learn about it by reading articles, watching videos, and attending conferences. The second step is to build projects on softwares like Pymol or Benchling, where you can simulate gene editing experiments. There are also many gene editing competitions, hackathons, and contests as well.

This is a fairly new space and holds incredible potential and opportunities for all of us.