GENE EDITING: CRISPR-CAS9
Gene editing is the engineering of changing the DNA of a living thing. Changing the DNA of an organism can change the protein made, resulting in a different phenotype than expected. Gene editing is used to change the DNA of organisms, usually eukaryotes, to help improve their quality of life. The way a gene editor works is that it slices the DNA at a specific point at where the DNA needs to be changed. For deletion, the "scissor" cut off a part of the DNA. Right after, the "scissor" cuts the DNA part off, the DNA repair mechanics automatically fix the DNA segment by attaching the two parts together, leaving the cut segment off. For insertion, the "scissors" break a part of the DNA. Then the DNA repair mechanics fix the strand. In order to fix the strand properly, a new strand of DNA comes in and is used as a template to fix the original piece of DNA. This is used to fix any mutations. However, as there is with any technology, there can be mistakes. For deletion, it is possible that the DNA strand doesn't correctly connect the DNA stand together. While connecting, it is also possible that some unwanted nucleotides are added or some nucleotides are lost. When this happens, there is a mutation in the gene which can change the overall phenotype. It is also possible that this mutation converts the gene section into an intron (the part of a gene which doesn't code for a phenotype). For insertion, it is also possible that some nucleotides are added or lost. Also, as with any copying,it is possible that the genes are copied wrong.
WHAT IS GENE EDITING?
WHAT ARE GENES?
Genes are units of heredity that carry genetic information from the parents to their children. These genes passed down is what results in the child being similar to their parents. Genes are made up of a specific sequences of nucleotides; these then code for a protein. The nucleotides are either called A, T, G, or C. Three nucleotides, for example, ATC, code for an amino acid. The amino acids created from the sequence then come together and finally make a protein. This process is called translation-transcription process. After created, the protein is used to make up a part of your body. For this reason, the nucleotides are considered the genotype because they are the genes which code for the protein. On the other hand, the protein made is considered the phenotype as it is the observable trait.
Since this process is very complex, mutations in genes are very common. A mutation in a gene can either be a deletion, addition, or substitution. A deletion in your gene takes away a nucleotide; an addition is when a nucleotide is added; lastly, a substitution is when one nucleotide is substituted for another. Most of the time, mutations don't have an effect on the protein made because there are many different sequences of nucleotides which code for the same amino acid. However, mutations can be detrimental, too. A mutation can cause the wrong protein to made, resulting in the job of the protein not being done. Also, changes in the nucleotide sequence can cause a malignant protein to be made.
WHAT IS CHRONIC PAIN?
Chronic pain is continuous pain that lasts for over 6 weeks. Chronic pain is when your nerves continuously fire pain signals to your brain, even if there isn't any pain inducing incident. Chronic pain can be caused by a previous injury or a genetic disorder. There have been many genes found that when mutated can cause chronic pain.
CRISPR-CAS9
WHAT IS GENE EDITING USED FOR?
ARE THERE GENES THAT RELATE TO CHRONIC PAIN?
Many studies have found that mutations in certain genes can cause chronic pain. I have done a project which looks at the correlation of certain genes with chronic pain and if there were any common genes found which cause different types of chronic pains. In my project, I found that mutations in interleukin genes cause many different types of chronic pain. Interleukins are proteins which are secreted from white blood cells. These cells then signal for more blood flow to the hurt area. These signals may cause nerve stimulation which causes pain. Mutation in these proteins can cause excess stimulation of nerves and create pain in the patients. Because mutations cannot heal themselves, mutations in genes which code for interleukins can cause chronic pain.
In 2015, a baby girl had been cured from leukemia. Being cured from cancer is not something that happens very commonly. However, this case was special because the baby who defeated cancer received help from gene editing. Because of gene editing, she was able to reduce the amount of mutations she suffered, therefore taking away her cancer. One of the main uses for gene editing is to help defeat diseases within patients. Many diseases, such as cancer, are because of mutations in genes. Through gene editing, scientists can fix the problem in their patient by altering their gene. Another major usage of gene editing is to help scientists better study genetics and diseases related to genes. Through the gene editing technology, scientist can better understand specific genes and their influence on our bodies. In addition to this, they can study how mutations in certain genes can impact us. This paragraph only mentioned about the benefits that gene editing can do, but there are also many harms which tag along with it, too.
CRISPR was first found in 1987 in Japan. While studying E.coli, the scientists found a repeating sequences of DNA separated by another strand of non-repeating DNA "spacers." These were later found to help increase the immunity of the bacteria because they store the genetic information of a virus. When a virus infects the bacteria, the bacteria takes the genetic information of the virus and places it into the "spacer" sections. This helps the immunity of the bacteria because when another foreign DNA enters the bacteria, the RNA molecule can take the previous DNA sequence and the Cas protein can disable it. Cas proteins are proteins which "unzip" and cut out a piece of the DNA in a genome. This was all found in bacteria, a much simpler version than in human, but scientists were still able to modify this system in humans to edit out genes. The crRNA (CRISPR RNA) would find itself in a Cas protein. Then the tracRNA would hold the crRNA in place. This helps direct where the gene would get cut. After this, the Cas protein cuts the DNA and while this happens, a new segment of DNA, which desired, gets inserted into the deleted section of the gene. In this tool, the protein used is a Cas9 protein. This technology is easier, cheaper, and more efficient compared to the previous gene editing technologies.
The CRISPR-Cas9 was developed in 2012 by Jennifer Doudna and Emmanuelle Charpentier. They were both at the University of California, Berkley when they found out how to manipulate the CRISPR-Cas9 system. Although it was a great invention, many bad effects came along with it. As the product is not fully developed, there is a very high chance of mistake with the system. In addition to this, people could abuse the product and create "designer babies."