What Is CRISPR?
Updated on February 18th, 2019
You may have heard of CRISPR — a genetic technology tool that allows scientists to change the genetic code of living organisms. But what is this tool, and how does it work? And what does CRISPR even stand for?
Before getting into just what CRISPR is, you should know that this real-life, while it seems straight out of science fiction, is offering up endless applications and abilities for today’s genetic scientists. And many of those functions have the potential to improve life for people all across the globe — by tackling huge problems such as curing cancer, reducing food shortages due to our changing climate, and more.
Who Is CRISPR?
So, what exactly is CRISPR? Well, first off, it’s not a who, but rather, a naturally occurring tool discovered by scientists.
The acronym stands for Clustered Regularly Interspaced Short Palindromic Repeats. In the simplest sense, CRISPR is a series of small, repeating genetic chains (also called DNA sequences) that have small spaces in between.
CRISPR is found naturally in the genetic code of bacteria, and it’s what those bacteria use to protect themselves from viruses. It’s also present in single-celled organisms called archaea.
Bacteria are amazingly able to use CRISPR as a defense by remembering the short, repeating CRISPR chains of viruses that attack them. They then incorporate the virus’ DNA into their own genetic code. This acts as a kind of vaccination, making it difficult for the virus to attack again, and protecting the bacteria in the future.
But there’s more — by pulling a virus’ DNA into their own, the genes of bacteria are then able to make enzymes (a form of proteins) that evolve alongside CRISPR. These enzymes have the ability to act just like scissors, allowing them to cut into DNA and make modifications.
That sounds pretty amazing, right? Interestingly, scientists have understood for some time that bacteria had this ability, but researchers just weren’t exactly sure how it worked. In fact, it wasn’t until around 2017 that researchers were able to see this process it in action.
In the short time since, genetic scientists have been able to build a new function for CRISPR: finding genetic material that may be for a specific function or ability, or broken, and replacing it with better working material. For example, researchers are now able to find genes that cause disease and replace them with a repaired version that “turns off” the gene and prevents disease. The process works in three basic steps:
- A segment of RNA — genetic material related and similar to DNA — called Guide RNA is created in a laboratory and used to locate the specific gene researchers are hunting for. Guide RNA acts as a kind of search tool or GPS for researchers, making it easy to find just what they’re looking for.
- The CRISPR enzymes are put to work cutting out the selected portions of broken or unwanted DNA. Two “cuts” are made — one right before the selected gene’s code, and one right after.
- The final step has scientists input the repaired piece of DNA into the genetic chain. This piece of DNA is placed in the small space created by the CRISPR process. In theory, the strand of DNA that was suffering from a error that caused a disease or health condition is repaired, meaning that the disease has been healed on a genetic level.
What Is The History Of CRISPR?
The advancements in understanding CRISPR and its uses have moved rapidly since researchers were able to better understand just how it works.
But researchers have known about Cripsr since the late 1980s. Genetic scientists discovered the CRISPR process in 1987, though it took nearly two decades for major advancements in understanding CRISPR and its uses to move forward. By 2008, a group of microbiologist researchers attempted to file a patent on work related to CRISPR research, though the rejected patent didn’t show strong, conclusive uses or findings for CRISPR.
Four years later, collaborative work by scientists Jennifer Doudna and Emmanuelle Charpentier brought an understanding of CRISPR’s process and potential uses to the forefront. Within a year, in 2013, Dr. Feng Zhang and Dr. George Church moved CRISPR research forward by presenting potential therapeutic uses for CRISPR through experiments on human cells and rodent cells.
Within a short time, some of the first versions of CRISPR tools were created — some expanding on the CRISPR process in new ways. By late 2017, one research center called the Salk Institute for Biological Studies created a new modification of CRISPR’s abilities, which allows genetic scientists to turn genes on or off without even modifying strands of DNA at all — meaning any changes made could potentially be reversed.
What Does CRISPR Do?
CRISPRs potential uses span over a variety of industries and purposes. Some of the biggest potential uses for CRISPR include:
Health and Wellness Improvement
Most research utilizing CRISPR has involved mice because they share a large percentage of DNA with humans. So far, researchers have been able to disable genes in mice that lead to several conditions, such as HIV/AIDS infection, Huntington’s Disease, and muscular dystrophy.
There’s also the belief that CRISPR could be the tool that helps cure blindness, blood disorders, and even Cystic Fibrosis. When it comes to cancer research, some genetic scientists have worked towards using CRISPR as a way to cure cancers such as sarcomas, melanoma, and cancers that attack the body’s plasma and white blood cells.
Medicinal and Biotechnology Research
Many researchers in the pharmaceutical industry believe that CRISPR can be a strong tool at helping to speed up the development of new medications. CRISPR has the potential to help medication manufacturers make more customized drugs that are safer, work better, and can be released to consumers faster — which is a major concern in an industry where on average, it takes about 10 years for a new medication to receive approval from the U.S. Food and Drug Administration (FDA).
Because CRISPR is also an inexpensive tool, there’s the possibility that it’s use could also reduce the cost of medications for the people who rely on them daily.
Food and Agriculture
Tests of CRISPR have already been used in some countries to modify genetic traits of livestock breeds traditionally used for meat consumption, such as pigs, to create reduced-fat, healthier meat products. CRISPR even has uses for non-meat foods.
CRISPR has been used to fight sickness-causing bacteria found in dairy products and has potential uses in editing crops to become more resistant to climate change and disease that leads to crop failure. Some research in using CRISPR for food purposes has even lead to the creation of produce with new features, including enhanced or unusual flavorings, foods with higher amounts of nutrients and vitamins, and the ability to last longer after ripening and being harvest.
Are There Drawbacks To Using CRISPR?
As we know it now, CRISPR has unlimited uses. So, you may be wondering why CRISPR isn’t becoming the solution to curing and eradicating diseases right away.
While gene editing has been around and practiced long before CRISPR’s use, there are many ethical reasons and unknown answers surrounding the use of CRISPR technology for human health. Because the use of CRISPR is relatively new, researchers are still unsure of all potential side effects caused by editing the DNA of living beings.
One of the largest concerns about the use of CRISPR is that there’s not a clear understanding of if or how gene editing through CRISPR can have a domino effect of impacting other parts of DNA. Scientists are unsure if editing one single gene — for example, a gene that helps the body fight off HIV and creates immunity to the disease — could cause unintended consequences in another part of a chain of DNA.
Researchers believe that one potential outcome of gene editing could be unusual, abnormal tissue growth, which has the potential to lead to cancer development. So, before CRISPR can be put to use in all avenues of gene editing, there’s still much research to be done on how the process affects other genetic functions — though at least one scientist has pushed forth with CRISPR edits on humans, leaving the medical and research communities in an uproar.
In late 2018, one Chinese scientist presented research at an international summit for humane genome editing, claiming to have produced the first CRISPR-edited human children. Researcher He Jiankui claims to have edited the DNA of two embryos that were then implanted and used for in vitro fertilization (IVF) purposes.
He claims that a set of twin girls were born healthy following the CRISPR gene editing process, though research organizations across the globe have not been able to verify their existence. In response to the severe violation of ethical guidelines for researchers, which prohibit testing on humans, He has been shunned from the research community and is potentially facing criminal charges in China.
One large question the genetics research community has is about the long-term effects and potential health impacts that the reported twins will face as they grow older — and because there’s no clear understanding of CRISPR’s impact over the long run, there are no clear-cut answers about what kind of genetic issues the two children could face.
As far as other issues related to CRISPR limitations, there’s also concern that human bodies may not respond well to CRISPR’s edits of DNA. Some research has shown recipients of CRISPR editing have immune responses similar to allergic responses, while other research shows that human bodies may attack the enzymes used in the CRISPR process before the gene editing can be completed, making it hard to anticipate before starting if CRISPR will or won’t work.
Researchers are also concerned about creating what’s called a “mosaic generation.” Because CRISPR removes broken or undesirable chains of DNA and replaces them with modified genes, the outcome looks something similar to a tile mosaic — bits and pieces of DNA from various sources, all grouped together. Genetic scientists are concerned that a mosaic generation could occur, a situation where some cells divide and replicate as they normally do, while repaired cells may not.
This comes into play as researchers understand that CRISPR is a useful tool at turning particular genes on or off, but it hasn’t been the best way to completely repair a broken gene.
What Products And Services Does CRISPR Offer?
While there are limitations to how CRISPR’s uses, more and more research is expanding just how it can it can be used right now.
Several companies have spun out of research into CRISPR’s applications, and are providing a variety of gene editing services. Three of the largest, most well-funded CRISPR companies include:
Intellia Therapeutics is a gene editing company that uses CRISPR in research with a mission to eliminate genetically inherited health conditions. The company’s primary focus was to work towards cures for liver diseases and has initially expanded to research into ways CRISPR can cure eye, muscle, and central nervous system. Intellia Therapeutics has also partnered with Novartis, a health care company, for research purposes.
At Editas Medicine, the company uses CRISPR to work on a variety of research programs including disease that impact the liver, lungs, blood system, eyes, and muscles. Editas Medicine also focuses its research on ways that CRISPR can be used in curing cancer. In early 2019, the company released the news that it had made advances in using CRISPR technology to potentially treat a genetically inherited form of blindness called Leber congenital amaurosis 10.
Creating medications that treat cancer, diabetes, blood disorders such as sickle cell disease, and other disease is the main focus of CRISPR Therapeutics. Some of the company’s work has included creating new cancer medications that can help patients better fight off the disease.
CRISPR Therapeutics was founded by leading researcher Emmanuelle Charpentier, and the company openly shares the progress of its current research projects.
While these three companies play a large role in CRISPR uses and researcher, there’s still so much to learn about what CRISPR can do and how it can be utilized in a variety of industries. In fact, nearly 30 years after the discovery of CRISPR, there’s still so much to be learned about how it can potentially save and improve lives for people around the world.