Genetic disorders such as sickle cell anemia arise from mutations in one gene. These are known as monogenic disorders because they are on a single (‘mono’) gene. Our genes can mutate in various ways, including point, missense, and frame-shift mutations. So, how can we fix these? Before CRISPR, solutions were unclear. Now, CRISPR offers a promising fix.

Let's break down what CRISPR/Cas9 is and how it works:

CRISPR stands for Clusters of Regularly Interspaced Short Palindromic Repeats. CRISPR are specific DNA patterns. Cells with a nucleus use them to defend against viruses. Imagine CRISPR like a "wanted poster" in a sheriff's office. Each poster has information about a specific virus.

How Does CRISPR Work? 

When a virus inserts its DNA into a cell, the cell stores a piece of the virus' DNA as a spacer between CRISPR repeats. This is like adding a new "wanted poster" to their collection. 

The gRNA: Dispatching the Response 

The next time the virus enters a cell, it can use stored information to cut the cell's DNA, making it nonfunctional. Now, the cell can produce guide RNA (gRNA) to target the viral DNA. The gRNA consists of two parts: crRNA, which matches the virus, and tracrRNA, which brings in the Cas9 enzyme.

Cas9: The Molecular Scissors 

Cas9 is like the sheriff in this story. It attaches to the gRNA and travels along the DNA until it finds a match with the viral DNA sequence. Once it finds a match, Cas9 cuts that DNA, disabling the virus and protecting the bacteria.

CRISPR/Cas9 in Genetic Engineering: Editing Genes 

Scientists were amazed by how precise and effective CRISPR/Cas9 is at finding and cutting specific pieces of DNA. They saw its potential for editing genes in other organisms, including humans.

By changing the spacer sequence in CRISPR, scientists can direct Cas9 to cut any specific DNA sequence they choose. It lets them edit genes by disrupting, deleting, or inserting DNA. This can fix genetic disorders like B thalassemia and cystic fibrosis. However, the potential to genetically alter organisms before birth has caused controversy. While this is common practice for laboratory animals it is not legal to do the same with human genomes.

This type of genetic modification is called germline human genome editing. It is the earliest point at which genetic engineering could affect every cell in the body. This means that this has the potential to alter the person and their future family line permanently. This modification could take many forms, and because the genetic modifications are made before a person is born, they cannot consent, whether to prevent them from having a disease or to choose their eye colour (note that this is not possible yet!). Fears about genetically engineering humans include creating "designer babies" and increasing inequality. These treatments might only be affordable for some. Early access would unfairly benefit certain groups. Yet, for those with loved ones suffering from curable diseases, the dilemma becomes clearer. The benefits of eradicating diseases are significant. The film GATTACA explores these fears. It shows how "designer babies" face discrimination in jobs and education. Meanwhile, Zero to Engineering Hero Chapter 2 delves deeper into the topic and offers activities.

CRISPR/Cas9 is like a genetic Swiss army knife, capable of precise genetic surgery. It may fix genetic "typos." This offers hope for curing many diseases. Just as a sheriff defends a town, CRISPR/Cas9 fights genetic diseases. It does this by finding and fixing their molecular causes.

So what’s the difference between our genetic engineering kit and CRISPR? Our kits aren’t cutting DNA using the CRISPR system, we are simply adding genetic material that can be taken up by the cell through its membrane! We make the cells competent, like when we heat-shock them in a transformation buffer. Then, they willingly take up this material. Learn more by reading our blog post or check out the  book to learn more and give it a try!