Gene Therapy:

What is Gene Therapy: In gene therapy, the cells are modified by introducing working genes, thus becoming a part of the cell's genome. This chapter of genetic engineering is still under construction.
How is this possible? The vector carries the gene needed for the cell to be repaired. This gene from this virus is specifically designed to repair or add to the genome in the targeted cell.
What is a Vector: A vector is a genetically altered virus engineered to reconstruct pre-existing cells.

Possible Practical uses?
  • "Curing" Blindness
  • Gene therapy used to correct Cystic Fibrosis in the human body
    Gene therapy used to correct Cystic Fibrosis in the human body
    Removing or repressing cancer cells (Elizabeth T. is going into more detail on this specific use)
  • Sickle Cell Anemia
  • Cystic Fibrosis
  • Many more diseases and mutations
    • this is a new science in which the boundaries have barely been tested

How could gene therapy "cure" blindness?



In the video an eye's cells are compared to a factory and an assembly line. Adding the virus to the eye's cells will not replace the factory, but only the assembly line director. Blindness (and many other bodily malfunctions) are often caused by one defective gene or trait. If this defect in the genome can be replaced or rewritten, then the assembly line would create a working product, in this case a functioning eye. Further details are briefly explained in the above video.

Somatic Gene Therapy:
Using genetic Engineering to affect an isolated group of cells.

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As the diagram shows, the DNA is inserted into the virus and then merged with the cell. Once the new cell is created, it will lodge itself in the bone marrow and replicate. These replicated cells are sent to where the need to go. The cells just know where they need to go, scientists are looking for and explanation or understanding of this. Each new cell will eventually replace all pre-existing cells, or at least change the overall function of the cells, in example, fix the disorder or mutation present in the genome.

Germ-Line Gene Therapy
A more specific brand of gene therapy is germ line gene therapy. Germ line gene transfer is a type of gene therapy that specifically deals with the sperm and egg cells, the germ cells. The process and concept is the same as regular gene therapy; the main difference is that each one of these cells will combine with their match, either sperm or egg, to form a zygote. This zygote will then develop into a living, breathing human being. There are more ethical issues/debates raised in germ line gene transfer than most other types of genetic engineering.


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The above image demonstrates how it is possible to add a genetic code into a plasmid and then insert that plasmid into the human cell. When inserted into the cell, the plasmid will replicate with the cell inserting itself into the genome. Basically, this makes it possible to insert a "man-made" trait into the natural cell. One practical purpose for this technology would be to correct carrier traits in the genome such as colorblindness or hemophilia. However, this science raises many issues involving ethics.


This is a demonstration of how a treatment of Germ-Line Gene Transfer can be administered
This is a demonstration of how a treatment of Germ-Line Gene Transfer can be administered


Germ-Line gene therapy also has its risks. The inserted plasmid could affect the pre-existing genome. If this occurs, the cells could die immediately, die later on in its life, or horribly mutate the cell. Scientists are working on ways to remove the defective code of DNA and insert the plasmid directly into this created gap. Germ-Line gene therapy has not been tested on humans yet; however, it has been used on animals. The most successful attempt has happened with vermin.

Somatic vs. Germ-Line Gene Therapy

Somatic gene therapy has less of an effect on the body, but there is less of a chance of mutations occurring than in germ line therapy.
Germ-line therapy is a much newer process and there is more risk due to more unknown information.
Somatic gene therapy influences a specific group of cells whereas germ-line therapy affects the cells that produce a zygote and therefore influence every cell in the new body. If one thing goes wrong in the therapy, it will affect every cell in the zygote, therefore affecting everything in the new baby.

Ethical Issues:

The main issue brought up with any use of recombinant DNA is God. Theists and Atheists alike believe that there are moral issues involved in gene therapy. Theists believe that one should not "play God" and that gene therapy is wrong. Both Theists and Atheists believe that, if kept unchecked, gene therapy could develop into choosing every aspect of ones baby. Also, how can you put a price on fixing a mental issue, or a heart condition? This is one question that will slow the progression of applied gene therapy even if it is deemed moral and okay to practice.


Why Not gene therapy;
In this TedX video, Nick will take us on a journey regarding the pros and cons of gene therapy. The pros are marvelous and seem endless. If we can cure diseases such as ALD and sickle cell anemia then why not do gene therapy! The few cons include cost of research and payment options for parents. Because gene therapy is a one time treatment, and not multiple doctor visits happening over the span of may years, how do you pay for just one treatment? Do you pay one or two million dollars? Or do you pay the same cost as one simple doctor visit? These semantic issues need to be worked out for gene therapy to move to the next phase, distribution.



http://ghr.nlm.nih.gov/handbook/therapy/genetherapy
http://www.genome.gov/10004764
http://www.open.edu/openlearn/science-maths-technology/science/biology/gene-therapy/content-section-3
www.youtube.com

Discussion:


Blake Miranda: After reading through your post, the obvious benefits of germ-line gene therapy are clear, with the elimination of diseases such as color blindness becoming a very real possibility. But, my question is, if this therapy becomes put into regular use, what is to stop scientists from going even further? As i see it, there could definitely be ways of changing the genetic make up of children to determine their exact appearance, and even give them clear cut physical and/or mental advantages over non altered persons. It seems like there would be definite ethical issues to accompany these as well, and i was wondering what these would be?

Jason: Through the use of recombinant DNA technology, cell modification and gene therapy become possible. As Cole’s discussion post states, recombinant DNA technology allows for the insertion of “man-made” traits, through the use of plasmid injections, thus allowing scientists to correct certain genetic defects or even produce desired (although sometimes unnatural) traits. So yes, Blake, you are completely correct in that physical and/or mental advantages can result from alteration of genes. One literary example of this includes the novel, Flowers for Algernon, in which a mice and a man’s IQ’s are nearly tripled. However, real-world examples include the development of glow-in-the-dark cats, pollution fighting plants, and even venomous cabbage! (http://www.mnn.com/green-tech/research-innovations/photos/12-bizarre-examples-of-genetic-engineering/pollution-fighting) The only significant things that stand in the way of genetic altering/enhancement are corporations that are concerned with the ethical and safety issues of these processes. Safety issues include possible defects resulting from these “enhancements” and the concern over scientific readiness. Some claim that germ-line engineering must be further examined in order to have clarity over the long-term effects. Some ethical concerns include how the alterations will affect the “fairness” of academic and athletic competitions. Another concern is that the obviously high amount of money needed to pay for the procedure might cause a widening performance gap between the rich and poor. However, the most significant and widely supported ethical concern is the act of “playing God”. Many believe that scientists should not interfere with the inheritance of traits and the uniqueness of life that it brings with it. However, a large amount agrees that with the proper consent from one’s parent(s)/guardian(s) that the client should be allowed to undergo the procedure.


Jason: During the process of gene therapy, must a virus be the vector that transfers and injects the plasmid into the cells, or can bacteria also be utilized? If so, what are the certain traits and characteristics that are possessed by the virus that allow it to undergo this process? Also, how are the original DNA of a virus removed, and the new reparative (foreign) DNA added.

Gene mutations can result, if a gene has extra or a lack of bases, or even if the bases are arranged in the wrong order. I understand how a virus could add bases to an unfinished gene, but how can the virus remove or rearrange certain nucleotides from a genetic sequence?

If the inserted plasmid initially works, but later becomes dormant, is it possible to know what would then happen to the cells, and consequently to the organ/body structure? Would the cells revert to their original state or after being inserted, would the body recognize and be able to reproduce the repaired genetic code on its own?

The process of using a virus as a carrier to fix genetic mutations seems very similar to the use of recombinant DNA technology. What is the difference, or are they maybe the same? (Found on page 784 of the prentice hall chemistry textbook).

Lastly, just as a suggestion, some ethical concerns would be the taking away of the uniqueness of life or the possibility that God or some other celestial deity had created genetic mutations for a certain purpose?
The only was that has been discovered so far to insert new DNA into pre-existing cells is to use a virus. This virus has most likely been man-made in a lab. The RNA stays the same in the virus but new material is added. The virus knows how to transfer the inserted genetic code into the cells in the body. Scientists do not yet understand how the virus's know how to do this, they just do. Other times, the virus will infect cells and correct the dysfunctional trait and then make themselves a home in the blood marrow. They then replicate here and send the new, correct cells into the bloodstream and throughout the body.

There is always a risk of mutations, and incorrect order of genetic code with this new therapy. These are reasons why this technology is not public and also why it is still under development.

This treatment is a lasting, one time deal and has not reverted back to its original DNA so far. This might be a possibility but i have not researched enough yet to answer this question in detail.

I believe that this is the same as using recombinant DNA technology.

Thank you for you're suggestion, those are all accurate and I will later add answers to this question to my page, I have just not had enough time yet.
I hope this helped Jason, if you have any more questions feel free to ask!!:)
-Cole K.'s answer to Jason's question


I have looked back and done my research, Jason. All gene therapy, genetic engineering, stem cell use/research, many other aspects of biochemistry all use recombinant DNA to affect the pre-existing genome. I hope the helps!
-Cole K.

Cole, would it be possible, as gene therapy develops, to mix and match traits from more than two parents and produce one zygote with the desired traits?
-Anuj R.

In response to Anuj:
Yes this is possible to have three parent babies, but not in the way that your asking. Scientists cannot yet take genes from three separate parents and combine them to make one baby with three parents. Instead, if a mother is likely to pass down a birth defect, this defect would be stored in the Mitochondrial DNA. To ensure this trait would not be passed down to their children, scientists can take a third party cell with one hundred percent correct mitochondrial DNA and replace the faulty DNA with this third party DNA. This process technically makes the zygote be created with three parents responsible for its unique genome.

This video explains more in depth the process and offers the alternative options for parents with faulty DNA that will possibly be passed on to their children:


I hope this helps Anuj!:)
-Cole K.

Yes, this does help. Now I have a better idea of the topic. There is a very unique animal that I would like to discuss: the African bullfrog. This animal has the ability to switch sexes in the event of a single gender or almost single gender population (almost all are male, or almost all are female). Theoretically, would it be possible to give humans this capability?
-Anuj R.

I believe that if the gene or genetic sequence that causes this ability to switch sexes can be located and replicated, that it could be inserted into a vector and deployed into the body. The only question i have to ask you is, why? It would be helpful if there was an area of heavily populated males or females, but I do not believe this would ever be necessary. And also, there are surgeries that can do this... This is a very.. interesting question.
-Cole K.