CRISPR
#16
I learned about CRISPR in class a few months ago, and wanted to learn more about it and what it does.
What is CRISPR?
CRISPR, which is a gene-editing tool that allows scientists to selectively modify organisms’ DNA, stands for ‘clustered regularly interspaced short palindromic repeats’. CRISPR was first discovered and identified in E. coli in 1987.
CRISPR-Cas9 is the most commonly used and studied type of CRISPR system. Cas9 is short for CRISPR-associated protein 9, and it is the most used gene-editing nuclease because of its promise shown towards treating hereditary diseases and cancers.
Function
When a bacterium is infected with a virus, it is able to take bits of the virus's DNA and insert it into its own DNA. This creates segments called CRISPR arrays, which allow the bacterium to remember the virus. If the virus comes back, the bacterium produces RNA segments using the CRISPR arrays. These RNA segments are able to recognize and attach to certain areas of the virus’s DNA. To disable the virus, the bacterium simply uses a Cas protein (such as Cas9) to cut the virus’s DNA into pieces. This is a naturally occurring process in the bacterium.
Scientists have adapted this system into a DNA-editing tool. CRISPR has been very useful to scientists, as it has been used to help detect the SARS-CoV-2 virus, the virus that causes COVID-19. In recent years, CRISPR has been used to edit the genomes of human cells, mammals, fish, and insects.
CRISPR in Humans
CRISPR-Cas9 is still being researched and experimented with in hopes of being able to treat disorders and diseases like cystic fibrosis, sickle cell disease, cancer, heart disease, and HIV.
Scientists are still unsure about whether genome editing is safe in people, since there are many risks and death is possible (happened to a man with Duchenne Muscular Dystrophy in a clinical trial).
Ethical Issues
CRISPR can be used to edit gametes and early embryos, as well as somatic cells. This can raise concerns, since edits made to gametes and embryos can be passed to the next generation(s). CRISPR can also be used to enhance certain traits that are desirable, such as hair color, eye color, and height. Ethical concerns such as these are why scientists have called for a moratorium on uses of human germline editing until they can understand more about this subject.
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