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There are two methods to modify embryos. The most prominent and promising method is by using CRISPR gene editing technology which is a type of germline engineering. The science behind CRISPR technology is still developing and increasing in quality to ensure a safer procedure as people are anxious about the implications of using gene editing techniques that could eventually lead to many ethical implications and debates.
However, there are other methods which have their merits such as somatic editing, which differs from germline technology. This is because with somatic editing any changes, including side effects, are limited to the treated individual which means that the changes do not get passed onto further generations. This is a huge difference when compared to germline technology, where the edited gene is passed onto future generations.
This change is both potentially positive and negative as it could stop harmful side effects from passing on to future generations which wouldn’t respect their autonomy as they did not choose to have these harmful side effects. On the other hand, it would mean that the procedure would only have to take place once to have effect on upcoming generations which would be more efficient and prevent particular diseases from taking place.
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The method behind both procedures is also dissimilar due to the technology targeting different types of cells. In regards with germline technology, the modifications are made in very early development, as it targets the reproductive cells, which means that any changes target all the cells in the body. This leads to all the cells having the edited gene copied into them. This leads to the edited gene consequences being passed onto further generations which means that any potentially harmful side effects can be passed on.
One type of germline engineering, as mentioned before, is CRISPR which is “a complex of enzymes and genetic guides that together finds and edits DNA.” (Everything You Need to Know About Crispr Gene Editing by Megan Molteni on the 22/01/20).
The way this method takes place is first “they locate the sequence of the human genome one which is causing the problem.” (CRISPR explained by Mayo Clinic on the 22/01/20). The next step is to create a strand of RNA, which is called the guide RNA, that recognizes the target DNA sequence of the human genome of interest which may contain a defect, such as a disease, that they want to remove. This is because the RNA is “A molecule that helps “read” the genetic information contained in DNA.” (Explainer: how CRISPR works on the 22/01/20).
The reason why the guide RNA can locate the specific DNA strand is because the guide RNA is complimentary to the DNA strand, as it has complimentary bases, therefore it is able to locate the strand of DNA causing the problem. However, the guide RNA must be powerful enough to find the particular sequence of human genome that contains the defect as the human genome is huge so it is challenging to find the particular strand.
The guide RNA then forms a complex with cas9 which is a “lumpy, clam-shaped DNA-cutting protein” (Everything You Need to Know About Crispr Gene Editing by Megan Molteni on the 22/01/20). Cas9 is crucial as it cuts out the section of the gene that contains the defect. The next step is that the guide RNA becomes injected, alongside cas9, into the desired target cell, where the defect is situated. Next, the guide RNA locates where the editing activity should take place in the nucleus and it then takes cas9 to the precise location where the defected DNA is located so cas9 can cut the undesired part of the DNA off.
The reason why the complex is very sophisticated and works well is because both components complement one another so it results in an efficient system that tries to eliminate undesired characteristics by editing the unsought DNA. Once the complex is in the nucleus and it has located the strand, cas9 locks onto it and this results in the strand becoming unstable which means a bit of the double helix becomes unzipped.
This is crucial as it allows the RNA to enter the strand and check that it is the correct sequence. RNA is able to perform this task as it has complimentary bases so it’s bases will be able to pair up perfectly to the DNA strands bases. If the bases pair up correctly then this means that the DNA strand contains the defect, so “the guide RNA triggers cas9 to produce two pincer-like appendages, which cut the DNA in two.”(Everything You Need to Know About Crispr Gene Editing by Megan Molteni on the 22/01/20).
The end results of this process are that there is a break in both strands of DNA which the cell detects and tries to repair. (Paraphrasing – Everything You Need to Know About Crispr Gene Editing by Megan Molteni on the 22/01/20). The cells repair the break by joining the two ends loosely together. However, this process is extremely shoddy as it usually results in a mistake that causes the strand of DNA not to work therefore disabling the gene. This could be useful only sometimes. Alternatively, scientists can add replacement DNA to repair the gene instead of allowing the cell to disable it.
Pros and Cons of CRISPR Technology
One of the major pros of CRISPR technology is that it is much cheaper to use when compared to other methods such as somatic engineering. This is crucial because if we consider the practicality of CRISPR in real life scenarios it would mean that more people will be able to use this method which would mean that it isn’t only limited to the rich. This is important as it means the gap between social classes will not expand (see ethics section for expanded argument) due to CRISPR technology as it would be available to all regardless factors such as gender and wealth.
Also, CRISPR technology is more customizable as it allows the user to target a specific strand of DNA which makes this method very efficient. This is because scientists can make guide RNAs complimentary to any DNA strand which will allow cas9 to target any type of DNA strand.
Another important advantage CRISPR has when compared to other methods is that it doesn’t need to become paired with artificially made enzymes that cut off the undesired part of the DNA strand. This due to the fact that CRISPR secretes its own enzyme that undertakes this task, which is cas9. This means that less work would be needed to use this method which will reduce its price which would result in this type of method being more widely available to the general public.
On the other hand, the flaws of CRISPR technology are there as sometimes cas9 cuts an unintended section which could have devastating results on the human body because an important gene may be disabled. This could lead to numerous diseases which could have adverse effects on the human body. Also, as the advancements in CRISPR technology march forward, ethical principles are going to come into consideration because as humans we need to be able to understand that we aren’t in a position to create foetuses that have advantages in every category as it will lead to a tiered human system which could result in major conflicts due to the inequality between the genetically modified humans and regular humans.
How Somatic Engineering Works
The main difference between somatic and germline technology is that with somatic it only targets specific types of cells which means no other types of cells are affected. This means that any effects are only limited to the person who underwent the therapy which means that it doesn’t pass onto further generations.
Pros and Cons of Somatic Engineering
One of the major cons of the type of engineering is that it doesn’t get passed on to future generations which is a major deterrent. This is because it makes it more time consuming to undergo the therapy with every single person of one particular bloodline.
Also, another con of this type of engineering is the price, when compared to other methods. This is because it is significantly more expensive to undergo this therapy and when put into perspective it will have major cost implications as you would need to undergo this procedure multiples times in order to prevent recurrence of the condition in future generations.
However, a major pro is that it has been researched and tested for more than 20 years and that it is highly regulated. This means that whoever undergoes this procedure will have high confidence knowing it is relatively safe. Furthermore, this could mean that more people will be open to undergoing this treatment as they’d know they will be treated with a type of therapy that is relatively safe.
