Recently Discovered Side Effect of CRISPR Gene Editing

    CRISPR, short for clustered regularly interspaced short palindromic repeats, are found in prokaryotic genomes; they have nucleotide repeats and spacers. Associated with this family of DNA is Cas-9, which is an enzyme that has the ability to cut strands of DNA.

    Separate studies concluded that the Cas-9 enzyme can be directed to cut any region of DNA by changing crRNA's (CRISPR RNA) nucleotide sequence; fusing this with tracrRNA (trans-activating RNA) forms a guide RNA. George Church, a genetics professor at Harvard Medical School, stated "the [guide] RNA plus the protein [Cas-9] will cut -- like a pair of scissors -- the DNA at that site, and ideally nowhere else." After the region is cut, the cell will naturally repair this; this may introduce mutations or other changes.

    This genome editing tool is powerful. Diseases-causing mutations may be corrected in embryos to prevent future genetic disorders. Use of CRISPR-Cas9 may improve fertility treatments for couples with disease-causing mutations. Problems arise when the Cas-9 protein breaks a double strand (DSB induction). To repair this, microhomology-mediated end joining occurs; the occurs in the first cell cycle of the zygote, restoring the reading frames. In this process, half of the breaks remain unrepaired; a paternal allele is undetectable. After mitosis, chromosomes are lost.



These mutations provide significant challenges for correction.





https://www.livescience.com/58790-crispr-explained.html

https://www.the-scientist.com/news-opinion/crispr-gene-editing-prompts-chaos-in-dna-of-human-embryos-67668

https://www.cell.com/cell/fulltext/S0092-8674(20)31389-1

https://www.nytimes.com/2020/10/31/health/crispr-genetics-embryos.html

Gene Editing To Produce 'Super Dad' Livestock

 

Gene editing is not a new concept today. Many scientists as well as research are using these tools to improve the quality of life here on earth. Along with improving the quality of life, the quality of food fall right in that category. Researchers are using these tool to produce better meat for production. Gene editing not only will improve our food source, but it would back so-called "elite animals", animals with more value. Professor John Oatley says, "This can have a major impact on addressing food insecurity...less water, less feed, and fewer antibiotics in our animals". This would make a huge impact both financially and health wise. Through selective breeding as well as gene editing of the CRISPR gene to manipulate the genome is used in producing desired livestock. Also scientist may be able to bring back extinct animals through the use of frozen sperm to regenerate the species. This was just a little extra information that the article gave.

https://www.bbc.com/news/science-environment-54155152

https://jeb.biologists.org/content/223/Suppl_1/jeb207159

China Halts Work by Scientist Who Says He Edited Babies' Genes

         A scientist by the name of He Jiankui and his team are currently being investigated by authorities after revealing his gene editing experiments done on human babies. Genetic testing on human embryos is very much guarded, which is why it is such a huge deal. Gene editing is a very sensitive topic to a lot of people, including scientists, because it is seen as morally wrong as well as inhumane. A lot of genes are interconnected in some way, meaning one change in the genetic code of a human could change a lot of things, some good, some wouldn't matter too much, but a lot of them could cause extremely detrimental defects to the baby which is why it is such a serious experiment.
          In Dr. He's experiment he used crisprs in order to alter the embryos of two twin girls who were born last month. Crisprs are derived from the bacteria cell which have the ability to adopt the DNA of a virus or another outside DNA sequence. When the virus returns, the bacteria would be able to fight off the virus by producing segments of RNA which will attack the DNA of the newly introduced virus. The bacteria then use an enzyme (usually CAS9) in order to cut up the DNA, which would kill the virus. Dr. He would use the same procedure except that the virus would be replaced with human DNA from an embryo.

           Using the crispr would give Dr. He the ability to edit the genome of the embryo in order to genetically enhance the children with a particular gene that makes a human less likely to contract the disease, HIV.
          The reason I chose this article to review is because I think it is a major development in science that should and needs to be talked about. This one experiment has changed the way that we look at Genetic Science completely. Genetic editing has been referred and referenced in the human species before, but has never been used. Although it may be considered inhumane by some, it is a great leap in the world of science and how we have the ability to look at things now. Diseases may now be attacked genetically from the inside of the body like we never have been able to before. It is exciting, as well as very dangerous but we will have to see what the future holds.

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Original Article

Human Gene Editing Receives Science Panel’s Support

The National Academy of Science and the National Academy of Medicine are providing their support to the modification of the human embryo. Researchers believe by using these techniques it will prevent genetic disease that are passed down to future generations. The gene editing tool called Crispr- Cas9 is used to snip, insert, and delete the genetic material, which will be tested to treat diseases such as cancer, blindness, and other conditions. While Crispr is precise there is a fear of cutting the DNA where it's not meant to be cut and producing a child with a mutation. Furthermore, a fear of using these techniques to change the physical appearance and enhance intelligence. There are many concerns but years before this is applied to humans.

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