In the last four decades, scientists have carried out a lot of experiments into understanding genes, their functions, and how they could be edited. While reasonable progress has been made in understanding genetics, especially human genetics, editing the genes still requires expertise, money, and the usage of expensive technology.
However, the development of CRISPR, a new gene editing tool in 2012 changed the course of gene editing. This tool is regarded as being precise and effective in tweaking the genomes of humans, plants, and animals. What exactly is this tool? How is it used and what are the potential concerns? Keep reading for more information.
What is CRISPR?
Firstly, it is the short form of Clustered Regularly Interspaced Short Palindromic Repeats. It is a powerful tool that could be used to tweak genes. This simply means that the tool easily allows researchers or scientists to change the sequence of DNA and also modify the functions of genes. Nevertheless, it has other potential applications. With ongoing research, CRISPR has the potential to transform human health and medication. It could be used to treat and prevent some diseases, regulate immunity, enhance the growth of crops, etc.
The natural defense mechanism of bacteria was used in the development of CRISPR. Bacteria use RNA, a genetic messenger that is also close to DNA to repel attacks from viruses. While repelling this attack, these organisms will retain some bits of the virus’s DNA and store them in theirs. This stored DNA serves as a memory that will enable the organisms to quickly recognize and prevent future attacks from such viruses and other similar invaders.
How it works
Genomes contain various messages and information that are related to their DNA sequence. When editing genomes, these DNA sequences are changed and this also means a change to the information they contained. Through CRISPR, the editing could be done with the introduction of a cut that works like a pair of scissors in the DNA which will then trigger self-repair and the targeted changes will be introduced.
To direct CRISPR to the intended region of DNA, whether in humans, animals, or crops, scientists will only alter the sequence of the crRNA that binds to that of the target DNA. To simplify the process, crRNA and tracrRNA were fused to form RNA. To make it work, the researcher will first design up to 20 bases of the pairs sequence, which must all match with the gene of either the human, animal or plant you want to edit. However, the similarity of the pairs must be with the targeted gene alone and must not match with any other gene in the genome.
Once introduced, CRISPR will then cut the DNA at the intended gene and not ideally anywhere else in the genome. The process of self-repair will begin immediately. In the process of joining together the pieces of the cut DNA, the intended tweaking or editing will be carried out.
Risks and concerns about it
Despite its potential benefits, CRISPR is not yet a perfect tool because it is relatively new and this has raised some concerns. One of the major concerns of using CRISPR on humans is that it might not go to the targeted gene. For instance, it might locate and also cut any gene similar to the target. When this happens, it could lead to mutations in the other genes. There might not be any side effects, but it could also cause cancer.
The use of CRISPR on humans has been limited to cells that are not transferable to the next generation but this tool can also be used to edit the genes of the embryo. There has not been consensus about this editing which is also known as germline editing due to risk, lack of regulation, and ethical concerns. However, this doesn’t stop some researchers in the US, UK, and China from editing human embryos. This has raised concern about whether we will not have designer babies with enhanced genes that will increase their intelligence, muscle strength, and a lot more.
Another ethical concern about gene editing is that it could lead to an unintended ecological impact. For instance, an introduced trait in the gene of a target population could spread beyond such population through cross-breeding. Moreover, it could reduce the genetic uniqueness of a population, thereby putting concern for the survival of such a population.
This is not to say that efforts have not been made to regulate the usage of CRISPR. For instance, the U.S congress has banned any clinical trial that could lead to modified babies. Meanwhile, some organizations have also come up with guidelines on how to edit human embryos. With the guideline, gene editing will only be allowed for convincing reasons such as fixing faulty genes with no known medical alternatives. This will, however, be done under strict supervision.
With these concerns, research is ongoing on how to refine CRISPR. It has been revealed by the pioneer researchers that another enzyme could be used to edit genes in the future. The new enzymes will be smaller, more precise, and have more chances of success than the current one, Cas9 which could cut an unintended gene.
Moreover, CRISPR has also been used to develop cells that are invisible to the immune system in the body. This is because the body’s immune system will attack any foreign invader, including stem cells. When these stem cells are invisible, they will develop into adult cells that could be used to repair damaged organs in the body.
A red blood cell disease, known as beta-thalassemia disease has been cured by some CRISPR researchers. This happened when some CRISPR team took stem cells from a patient and edited them with CRISPR outside the body. This was done to increase the production of hemoglobin before the stem cell was transfused back into the body. With the announcement that CISPR-developed drug has been used to treat beta-thalassemia disease, researchers also believe that a similar approach could be used in the future to treat other blood-related diseases such as sickle cell anemia.
Research on CRISPR is advancing every day and some scientists believe that it could be used to change the course of human living for life.