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What is biotechnology?
What is biotechnology?
Biotechnology is any technical application that uses living organisms or derivatives of living organisms for a specific use.
On this page, we will talk about how biotechnology can be used to treat genetic disorders. A genetic disorder is a disorder that is caused by a mutation in the DNA. Since the DNA of a parent is passed down to the offspring, genetic disorder can be passed on as well.
The following is a list of a few examples of genetic disorders:
- Phenylketonuria (PKU)
- Down Syndrome (Trisomy 21)
- Edward's Syndrome (Trisomy 18)
- Cystic Fibrosis
- Turner Syndrome
- Hemophilia
- Sickle Cell Anemia
- Adenosine Deaminase Deficiency (ADA)
Genetic Screening
Genetic Screening
Genetic Screening is a biochemical or molecular test that is used to identify genetic disorders. There are many different types, some of which will be touched on later. All ages can be tested, elderly people and even an embryos. Genetic screening is done so that people can be better prepared for living with disorders that they or their loved ones may have. This brings up an ethical issue because sometimes when a person learns that they have a serious disease it is emotionally damaging and can affect that person's quality of life even while they are still healthy. In some cases, parents choose to have an abortion after having their baby genetically screened and finding out that it has a genetic disorder.
Since every cell in our bodies contains all our DNA, all that is needed for a genome scan is a few cells. Typically, a small swab will be taken from inside the patient's mouth or preferably a small prick of blood. The cells will be taken and organized in to a karyotype. A karyoptype is a chart organized to show the number of chromosomes in a person's genome. White blood cells are put into a solution to stimulate mitosis. The division is stopped at metaphase where the chromosomes are most visible. Then, the chromosomes are photographed and sorted.
The following picture is an example of a karyotype of a child with Downs Syndrome, also known as Trisomy 21. Trisomy 21 occurs when there is three copies of chromosome number 21 instead of two. Symptoms include a round, full face, short height, large forehead, and developmental and intellectual disabilities.
The video to the left describes in great detail the process of genetic testing. It uses the example of a girl who's mother has Huntingdon's Disease. The video explains the steps the girl will undergo and how the information is interpreted.
Expectant mothers can have their babies genetically screened even while it is still inside the womb. There are two procedures where this can be done, they are called amniocentesis and chorionic villus sampling (CVS). An amniocentesis (Amniotic Fluid Testing) is when a small sample of amniotic fluid is removed using a long needle and then tested. CVS is when a small sample of tissue is taken from the place where the uterus and placenta meet. CVS is done earlier than amniocentesis but is more risky and can lead to a miscarriage. These tests help the parents to be better prepared for when they have their child.
This video discusses what genetic screening can and can't teach you. It goes through all the negative and positive effects of genetic screening, focusing mostly on cancer.
Most people who are screened receive negative results but that does not mean they will for sure get cancer. Only a small percentage receive positive results and do not have any potentially harmful mutations.
Gene Therapy
Gene Therapy
Gene therapy is when a healthy gene is moved into a cell that has a missing or defective gene in order to correct a genetic disorder. There are three types of gene therapy:
- Gene Insertion
- Gene Removal
- Gene Replacement
Scientists have many hopes for what gene therapy will be able to accomplish in the future but as of now it is still extremely new and risky.
Germ-line therapy is when a gene is inserted into a reproductive cell (sperm or egg). This means that the changes that are made can be passed on to future generations. While this can spare offspring from inheriting severe genetic disorders, germ-line therapy is unpredictable at this point in time and brings up many ethical questions such as, "is it right to modify someone's genetic material when they can not give their consent?", or, "is it worth the risk of possible unknown mutations?". For these reasons germ-line therapy is not yet legal to use as a form of treatment in humans at this point in time.
Somatic gene therapy is when genes are inserted into the somatic cells. Somatic cells are any cells that are not reproductive cells; the changes will not be passed on to offspring but rather are restricted to the individual.
Palmiter & Brinster
Palmiter & Brinster
In 1982 Richard Palmiter and Ralph Brinster began an experiment to explore gene therapy. They took a growth hormone gene from a rat and inserted it into fertilized mouse eggs and then implanted the eggs into a surrogate mother. Only 7 of the offspring ended up carrying the fusion gene. All 21 mice were born the same size, but 6 out of the 7 mice carrying the fusion gene grew to be about twice as large as their litter mates.
The next step was to try to cure a genetic growth hormone deficiency using this new technique. Palmiter and Brinster took fertilized eggs from mutant dwarf mice and inserted a normal copy of the growth hormone gene and then implanted the eggs into surrogate mothers. The offspring were called transgenic, simply meaning that they contained genetic material from an unrelated organism. The transgenic mice grew larger than their parents. Palmiter and Brinster concluded that the genetic deficiency had been corrected.
Overall, Palmiter and Brinster started a worldwide revolution in genetic engineering. They were the first to demonstrate that indeed new genes can be introduced to the mammalian germ line. Transgenic mice are now used in laboratories all around the world to study a wide variety of things ranging from cancer biology and cardiovascular disease all the way to hair loss and abnormal behavior.
William French Anderson
William French Anderson
In the 1990s, French Anderson and his colleagues carried out the first successful use of somatic gene therapy with a human subject; a 4 year old girl with adenosine deaminase deficiency (ADA) named Ashanti DeSilva. ADA stops the white blood cells from maturing which causes severe immunodeficiency. Children with ADA lack most of the body's immune protection against bacteria, fungi, and viruses and most do not live to reach puberty. First, mature white blood cells were removed and isolated. The researchers then injected a functional ADA gene into the cells. This only provided a temporary cure for Ashanti. The reason this does not work long term is because white blood cells do not divide and only have a finite lifetime. For this procedure to work it must be repeated every few months. Ashanti is now 31 and still receiving this treatment as well as a direct dose of the normal enzyme.
The consensus based on Anderson's work was mixed but there is no doubt that it has had a huge impact on the emerging field of gene therapy. In 2004 Anderson was arrested for sexually assaulting a young girl and in 2005 he was accused of sexually assaulting a young boy but because of insufficient evidence the charges were dropped. In 2007 he was sentenced to 14 years in prison and has not been able to continue his work.
Sickle Cell Anemia
Sickle Cell Anemia
Gene therapy has provided a permanent cure for sickle cell anemia. Sickle cell anemia is when the there is a mutated form of hemoglobin which distorts the red blood cells into a C-like shape causing them to not be able to carry oxygen efficiently. The first successful trial occurred in 1998. Physicians replaced the bone marrow cells of a 13 year old boy with stem cells from an umbilical cord of an unrelated infant. The stem cells produced healthy bone marrow and the boy was cured.
Overall Success of Somatic Gene Therapy: Worth it?
Overall Success of Somatic Gene Therapy: Worth it?
Although there have been a few cases of successful gene therapy it has not been what everyone has hoped. Not much progress has been made since Anderson's trial but rather there have been some major setbacks. In 1999 a teenage boy died as a result of the trial, the viral vector being used in his trial caused a severe immune response. In other cases, some retrovirus vectors used have caused leukemia-like conditions. For this reason somatic gene therapy has not been approved as an effective treatment for humans genetic diseases. On the positive side, there has been success in correcting genetic disorders in mammals and scientists are continuing to work hard in research and clinical trials.
the ethics
the ethics
Many are concerned about the direction that genetic biotechnology is taking us. As Christians the following questions are often heard:
- Is this playing God?
- Is this a slippery slope?
A factor to consider is that somatic gene therapy does not effect offspring. This means that genes 'far down the line' are not being modified. Somatic gene therapy is similar to simply curing a disease in the same way that a surgeon does.
Another factor is that God cannot be played. Whether we are asking the question meaning "are we pretending to be God?" or "are we trying to beat God?", neither can be done. No matter how advanced humans become we will not reach the same power and control over life that God has. Doctors can choose whether to treat a patient but in the end it is God who decides whether to spare the life or take it. We cannot over power God, it's simply impossible. Every truth that we discover is from God, yet our knowledge is pale in comparison to His. In conclusion, we will never be able to be or beat God.
Gene modification has the potential to go in many directions. While it could be used in the future for much good it could also be used for much else. For example, some worry about the idea of "designer babies." While genetically modifying a child can be used for health benefits it can also be used to pick and choose certain genes in your child that have nothing to do with his or her health. Some ask the question, "will this technology be available to all people around the world or would we be essentially creating a 'superior race', while leaving others behind?" Another factor is that designer babies are conceived in a lab using some form of assisted reproductive technologies (ARTs) which usually involve the discard or storage of living embryos. While most agree that it is wrong to 'design a baby', some want to throw all genetic biotechnology away because of the belief that it will lead us down 'a slippery slope', meaning it will tempt us more and more to use this technology for the wrong reasons.
The video to the right describes the CRISPR-Cas9 process. The CRISPR-Cas9 process is the newest and most efficient way to repair or replace sections of DNA. This video also discusses the ethics of designing babies.
We are left with the question: where will genetic biotechnology take us in the future?
Bibliography
Bibliography
- White-McMahon, M., & Fraser, D., & LeDrew, B., & Vavitsas, A. (2012). Nelson Biology 12. Toronto, ON: Nelson Biology 12. Toronto, ON: Nelson Education Ltd.
- Dulson, J., & Fraser, D., & LeDrew, B., & Vavitsas, A. (2011). Nelson Biology 11. Toronto, ON: Nelson Education Ltd.
- https://www.youtube.com/watch?v=-cu_0rctmeM
- https://en.wikipedia.org/wiki/Amniocentesis
- https://www.google.ca/search?q=amniocentesis&ie=utf-8&oe=utf-8&gws_rd=cr&ei=lCDsWP3rN4LejwTFioaIDQ
- https://www.google.ca/search?q=amniocentesis&ie=utf-8&oe=utf-8&gws_rd=cr&ei=lCDsWP3rN4LejwTFioaIDQ#q=chorionic+villus+sampling
- https://www.youtube.com/watch?v=M7X-brwdGws
- https://ssl.gstatic.com/atari/images/favicon_2.ico
- https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcRJyp9E8a19PEpsjzRmKNV3deb4VjFlFWUXf6eAg_WeyaaCEF0XmftyYuc3
- https://www.google.ca/search?q=transgenic&ie=utf-8&oe=utf-8&gws_rd=cr&ei=dhzpWJ3ZMMa4jwSm16iQDA
- https://en.wikipedia.org/wiki/Ralph_L._Brinster
- http://www.nature.com/nature/journal/v300/n5893/abs/300611a0.html
- https://en.wikipedia.org/wiki/William_French_Anderson
- https://www.youtube.com/watch?v=lHesvjW1bKM
- https://ssl.gstatic.com/atari/images/favicon_2.ico
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