What is CRISPR?

Clustered regularly interspaced short palindromic repeats. CRISPR. In scientific terms, CRISPR are short segments of DNA comprised of repeating base sequences and is the foundation for a contemporary gene editing technology referred to as CRISPR-Cas9. Ultimately, these short sequences can be programmed to target and edit particular stretches of DNA. The product is a modified gene in a living cell, creating the possibility of correcting harmful mutations that can lead to genetic diseases.

How does it work?

In order to change a mutation in DNA, CRISPR-Cas9 utilizes 2 molecules: Cas9 and a segment of RNA. Cas9 is an enzyme that operates like scissors, capable of cutting the double-helix of DNA at the target location. Once the DNA is cut, segments can then be removed or added.

The RNA serves as a molecular guide in order to position Cas9 to the correct location. It also binds to the DNA before Cas9 intervenes. In order to construct the guide RNA, the sequence is engineered to match the desired sequence by presenting the appropriate base pairs. This way, the RNA will only bind where the correct base pairs align, or the target location.

Once Cas9 has cut the DNA, the cell repair mechanisms identify damage has been made, and begin to repair. The repair typically results with the original sequence or base pair rather than the mutation.

Where does it come from?

CRISPR was inspired by the defense mechanisms of certain microorganisms including bacteria. Bacteria respond to invading pathogens and viruses by taking a section of the pathogen's DNA and incorporating it into their own by using the Cas enzyme. The compiled sequence is known as CRISPR, and the microorganisms use CRISPR in order to protect themselves from future pathogens and viruses.

Scientists borrowed CRISPR from bacteria in 2012, modifying it into a gene-editing tool.

What is CRISPR used for?

The main target (as of now) is to mend mutations that lead to genetic disorders and health complications such as cancer and Huntington's disease. It also has future intentions to create improved versions of existing treatments, such as stem cell therapy. Using CRISPR in stem cell therapy would result with a tissue or product more specified to the area it intends to treat.

What are the ethical issues of CRISPR?

CRISPR poses the opportunity for genetic editing that leads to "designer babies". While that is not the original intention, the possibility of eradicating disadvantageous characteristics such as peanut allergies or weak immune systems can easily serve as a gateway to manipulating favorable traits such as height and eye color.