CRISPR-Cas9 is a way to edit genes by modifying, removing or adding sections to a DNA sequence. In recent years, CRISPR gene editing has emerged as a powerful tool, with applications ranging from preventing genetic defects and treating human disease to enhancing agricultural crops.
This increasingly popular technology has proved faster, cheaper and more effective than previous genome editing techniques. While CRISPR offers many benefits, its potential use in humans does come with ethical concerns attached.
What is CRISPR Gene Editing?
CRISPR stands for “clustered regularly interspaced short palindromic repeats.” Researchers use CRISPR to modify DNA sequences and alter gene function. Some compare it to a Swiss Army knife, those handy gadgets that contain a multitude of specialized tools designed for specific users, such as a camper, angler or gardener. The analogy works because scientists use CRISPR as a tool to selectively modify specific DNA.
The process is based on how single-celled bacteria protect themselves against attack. When bacteria fight off a virus, they capture a bit of the intruding virus’s DNA — and that bit is a clustered regularly interspaced short palindromic repeat. The bacteria then make an RNA copy of the CRISPR, and adds it to a list of known enemies.
When the next attack comes, the bacteria’s immune response is ready: It uses the RNA copy to fight back with a CRISPR-specific protein known as Cas9. The protein snips the intruding DNA and stops the attack.
Scientists use CRISPR in a similar way. They create CRISPR RNA copies and Cas9 proteins to target specific DNA. But rather than simply destroying that DNA, researchers use CRISPR to manipulate it in a process known as “gene editing.“
Researchers can target certain sequences in specific genes, using Cas-9 to snip DNA at the target site. The gap is then filled by a DNA template of the researchers’ choosing. This allows them to write-in and re-program genes while avoiding potentially harmful mutations. CRISPR can also be used to turn genes on and off, without altering their sequencing.
Potential Benefits of CRISPR
CRISPR-Cas9 has opened up a world of possibilities and potential benefits. CRISPR is already widely employed in scientific research in areas such as enhancing agricultural crops in terms of disease and pest resistance; heat, cold and herbicide tolerance; crop size and weight; and more.
CRISPR has the potential to transform human health and medicine, as well. The technology may allow for the treatment and prevention of medical concerns, from cancer to high cholesterol and neurodegenerative diseases like Parkinson’s. It may also be used to correct genetically linked conditions, such as epilepsy, cystic fibrosis, cataracts and anemia.
However, research is still in the early stages and it’s not perfect. Regions of DNA outside the target areas may be affected, leading to unwanted mutations and consequences.
CRISPR’s potential use on humans also raises ethical concerns. Thus far, research has been confined to animal models and isolated human cells with a controversial exception: In 2020, three biophysicists were sentenced to prison for using CRISPR-Cas9 editing on human babies. The situation underscores the complex ethical issues of using gene-editing in humans.
What does the future hold? CRISPR has already accelerated scientific research, and scientists continue to develop and hone the technology. Given what we know so far, CRISPR offers the potential to significantly improve human life and health.
However, complex ethical concerns around gene modification remain and must be addressed, including issues of consent, diversity and ideas of genetic supremacy. CRISPR will push these conversations to the forefront, as it continues to push the envelope of scientific progress.