The CRISPR Gene Editing

One of the most important aspects of medicine is the study of diseases. Diseases ensure that the medical profession remains relevant because, in the absence of diseases, medicine would be outdated. Why has man not been able to eradicate all diseases, even though the medical industry has existed since man first set foot on earth? One may be curious. The simple explanation for this is that diseases frequently mutate, which forces doctors to create novel treatments for the transformed condition. A good example is the malaria parasite, which has evolved through time and become drug-resistant (NIH, 2014). The other reason is disease inheritance. Offspring tend to inherit genetic patterns from their parents; this also includes genetic diseases as Huntington disease (Im, Moon, & Kim, 2016). Human gene editing using CRISPR is one of the new technologies in medicines that promise to provide solutions to these disease problems.

At a microscopic level, billions of cells combine to make up the human body. In every cell, there are chromosomes that contain deoxyribonucleic acid in short DNA. Genes that play significant role in human development are the components that make up the DNA (Ledford, 2016). Genes make it possible for us as individuals to be unique for example difference in eye color, voice, appearance, and behavior of other features. Genes are also important, as they are the determinants of our overall health. There are diseases that develop due to the certain characteristics of the genes. By understanding these characteristics, scientists are now able to alter the genes as a method of curing these diseases. CRISPR is one of the tools that scientist use to alter genes. CRISPR has increased efficiency in gene editing making prevention and curing of diseases a through genes possibility.

CRISPR: How it works

Before the invention of CRISPR as a method of gene editing, scientist mostly utilized the use of radiation and chemicals to alter genes (Regalado, 2016). It did not take long for them to realize that this method was ineffective as it was difficult to specify where the altering should occur. This was a problem, as scientist could not control the process and the outcomes, which made use of radiation and chemicals unreliable. There was a need to develop a more efficient method (Gray, 2017). CRISPR is a method that has proven to be most effective. In addition, the method is affordable and timesaving.

Cluster Regular Interspaced Short Palindromic Repeats, in short CRISPR, is a method that easily enables scientist to make modification to the DNA. CRISPR enables scientist to modify the genome by giving them the ability to add or remove DNA sequence (Pawluk et al, 2016). This method is much popular since it gives scientist the ability to target the gene at the required strand in order to make modifications. According to Heidi Ledford, the power of CRISPR lies in two core components (2016). The first component is RNA molecule that is responsible for identifying the affected area. Once the identification of the affected area is done, the second component Cas9 a protein enzyme does the cutting. At this point, there is the option of the cell repairing the removed DNA strand. This method is not advisable as errors may occur as the cell does the repairs. Therefore, scientists prefer introducing a DNA template to aid in the repairs.

Editing of Genes

The identification of the DNA strand to modify is the hard part, once the identification of the DNA strand is complete; editing the gene becomes much simpler. The Cas9 acts as a scissors and cuts the undesired part of the DNA (Mali et al, 2013). After the cutting off undesired part, Cas9 protein enzyme that is still in the gene can be used to activate or inhibit feature of a gene. As an inhibitor, Cas9 repels other proteins, for example, RNA polymerase. Scientists term this process as CRISPR inhibition. There is also the reverse of this method, CRISPR activation where there is merging of Cas9 protein enzyme with a protein of the desired expression.

CRISPR use in Organism

Most of the research in CRISPR has been mainly on laboratory animals. The advantage of using animals is that animals are easy to acquire and study for long in controlled environments. In manipulation of genes using CRISPR, scientists have preferred studying it effects on flies, zebrafish, and mice (Ma & Lui, 2015). The reason for this is that flies, zebrafish and mice have simple genetic makeup that is easy to manipulate. In addition, their reproduction cycle is relatively fast and therefore it is easier to note the changes due to gene manipulation. In study of zebrafish, use of gRNA less than 20 nucleotides provided effectiveness of gene editing (Ma & Liu, 2015). Scientists replicated the same method in human T cells using chemically modified gRNA and reported a success in disruption of genes, though there is need for more research.

Example of CRISPR uses

CRISPR has shown great promises in curing cancer. The first live human trial began in 2016 in China. The patient had an advanced case of lung cancer and the cause was a gene abnormality that slowed down the growth of the patient’s immune system. The slow growth of the immune system facilitated increase of cancer cells in the patient lungs. Using CRISPR, scientists were able to alter his abnormal gene to enable normal reproduction of immune cells to fight cancer (Cyranoski, 2016). Apart from finding cure for cancer, there has been massive research in trying to incorporate gene editing in curing other diseases.

Advantages of CRISPR

The importance of CRISPR is numerous; the technology is new and full of potential. As for now, scientists are using CRISPR as tool to enable them to make changes to gene. This is important as by making changes and modification to genes, they are in a better position to understand the effects of those changes. The information gathered in these gene experiments is crucial as it provides a platform for scientists understand the workings of genes (Kaiser, 2016). Currently, gene alteration experiments allowed only to research animals. Use of human samples is illegal and strictly prohibited. Some countries though have allowed gene experiments in early human embryos. If successful, the CRISPR will create solutions to modern disease problems.

Disadvantages of CRISPR

Use of CRISPR in gene editing has raised all types of concerns majorly moral, ethical, legal and religious. There are people who believe that gene editing is a gray area. This is due to its sensitivity as altering DNA has consequences we currently do not yet understand. This concern is true as the field lacks enough supporting data to suggest otherwise. In her article 3 big questions about gene editing, Mary Marcus argues that ‘Tampering with genes is risky as one can turn off important functionality and turn on really bad ones’ (2015).

The other apparent disadvantage of CRISPR is in terms of cost. Despite the fact that the technology is a promising field, it is very expensive. Researchers speculate that even if there was the implementation of the technology, it will only benefit the rich who have enough finances to cater for the procedures. This technology is discriminatory in nature, as people from middle-income and poor backgrounds will suffer for decades before the treatment becomes affordable.

Future of CRISPR

There is a lot of research and trials that scientists are conducting in gene editing using CRISPR. Since the field is still in its infant stages, progress is slow due to lack of enough data to cross-reference. Although the situation is slowly changing as different nations are exploring gene editing. In future, scientist will have enough data and knowledge that will be essential in curing diseases brought about by genes. There is even a possibility that scientists will be able to develop genetic tailor-made medicine for patients. Information regarding editing of genes is important as scientist can use that information in developing cure to incurable diseases as cancer, hemophilia, and HIV

The ability to edit genes is also important, as it will enable scientists in future to enhance certain parts of the genome. Traits like enhanced memory, strength, improved brain capabilities and resistant to diseases among others will be possible through altering the genes. This means that man will be able to better adapt to his environment, as his genetic make-up will favor him. It will also mean that man will be immune from diseases in his entire lifetime. This is factor is beneficial to individuals as it reduces medical cost and the economy as it ensures availability of labor.

Conclusion

CRISPR is a new type of gene editing method that had replaced traditional approaches due to its effectiveness and affordability. This technology is still in its infant stages but its fruits are already showing. Currently, there is the use of CRISPR in treating cancer trial patients. In addition, the researchers are coming up with creative ways to cure hereditary diseases. In the near future, scientist aims to use this technology to suppress or activate desired traits in offspring. The advantage of this is that there will be no more issues of hereditary diseases. In addition, altering genes will give scientist the ability to enhance traits as physical health and resistance to diseases. In spite of CRISPR benefits, there are various concerns that question the safety of this method. At present, there have not been enough studies to show the effects of gene editing. Scientists are using CRISPR with significant amount of caution as messing with genes has significant consequences.





References

Cyranoski, D. (2016). CRISPR gene-editing tested in a person for the first time. Nature, 539(7630), 479-479.

Gray, K. (2017). What is genome editing and how does it work?. Wellcome Trust. Retrieved 2 February 2017, from https://blog.wellcome.ac.uk/2015/09/10/what-is-genome-editing-and-how-does-it-work/

Im, W., Moon, J., & Kim, M. (2016). Applications of CRISPR/Cas9 for Gene Editing in Hereditary Movement Disorders. Journal Of Movement Disorders, 9(3), 136-143.

Kaiser, J. (2016). The gene editor CRISPR won’t fully fix sick people anytime soon. Here’s why. Science | AAAS. Retrieved 2 February 2017, from http://www.sciencemag.org/news/2016/05/gene-editor-crispr-won-t-fully-fix-sick-people-anytime-soon-here-s-why

Ledford, H. (2016). CRISPR: gene editing is just the beginning. Nature, 531(7593), 156-159.

Ma, D. & Liu, F. (2015). Genome Editing and Its Applications in Model Organisms. Genomics, Proteomics & Bioinformatics, 13(6), 336-344.

Mali, P., Yang, L., Esvelt, K., Aach, J., Guell, M., & DiCarlo, J. et al. (2013). RNA-Guided Human Genome Engineering via Cas9. Science, 339(6121), 823-826.

Marcus, M. (2015). 3 big questions about human gene editing. Cbsnews.com. Retrieved 2 February 2017, from http://www.cbsnews.com/news/human-gene-editing-big-questions/

Pawluk, A., Amrani, N., Zhang, Y., Garcia, B., Hidalgo-Reyes, Y., & Lee, J. et al. (2016). Naturally Occurring Off-Switches for CRISPR-Cas9. Cell, 167(7), 1829-1838.e9.

Regalado, A. (2016). A Scientist's Contested History of CRISPR. MIT Technology Review. Retrieved 2 February 2017, from https://www.technologyreview.com/s/545741/a-scientists-contested-history-of-crispr/

Study shows parasite mutation behind drug-resistant malaria in Cambodia. (2014). NIH. Retrieved 2 February 2017, from https://www.fic.nih.gov/News/GlobalHealthMatters/january-february-2014/Pages/malaria-drug-resistance-mutation-niaid.aspx