Reproductive Cloning Technology example essay topic

Human Cloning The possibility of human cloning was raised when Scottish scientists, led by Dr. Ian Wilmut at the Roslin Institute, created the much-celebrated sheep "Dolly". Being the first mammal ever cloned this aroused worldwide interest and concern because of its scientific and ethical implications. The feat, cited by "Science Magazine" as the "breakthrough of 1997", also generated uncertainty over the meaning of "cloning" -- an umbrella term traditionally used by scientists to describe different processes for duplicating biological material. Since this creation, mice, goats, cows and pigs have been successfully cloned around the world. This has made human cloning a real possibility. Cloning is the production of one or more individual plants or animals that are genetically identical to another plant or animal.

It is different from natural fertilisation which is "sexual" reproduction that occurs when a sperm fertilised an egg. In normal fertilisation the developing embryo (and person) has the genetic makeup or DNA of both parents 23 chromosomes from the female and 23 from the male. The embryo is the unique human organism with a novel genetic makeup having the full potential to develop to adulthood. Current definitions define "embryo" as follows: "the term 'human embryo or embryos' includes any organism that is derived by fertilisation, parthenogenesis, cloning, or any other means from one or more human gametes or human diploid cells".

Figure 1: Comparing cloned embryo's with fertilised embryo's Source: Available from URL: web (Accessed Sunday 15th August 2004) When the media report on cloning in the news, they are usually talking about only one type called reproductive cloning. There are different types of cloning however, and cloning technologies can be used for other purposes besides producing the genetic twin of another organism. A basic understanding of the different types of cloning is the key to taking an informed stance on current public policy issues and making the best possible personal decisions. The three main types of cloning are: 1.

Embryo cloning 2. Reproductive cloning 3. Therapeutic cloning Embryo cloning Embryo cloning might be more accurately called "artificial twinning", because it simulates the mechanism by which twins naturally develop. It involves removing one or more cells from an embryo and encouraging the cell to develop into a separate embryo with the same DNA as the original. It has been successfully carried out for years on many species of animals. Some very limited experimentation has been done on human embryos.

Nature itself is the greatest cloning agent. In about one of every 75 human conceptions, the fertilized ovum splits for some unknown reason and produces monozygotic (identical) twins. Each has a genetic makeup identical to the other. In cloning, this same operation is done intentionally in a laboratory. Figure 2: Cloning or Asexual Reproduction Source: The Center for Genetics and Society, Human Cloning and Genetic Modification: The Basic Science You Need to Know [online] Available from URL: web (Accessed Sunday 15th August 2004) Procedure Human embryo cloning starts with a standard in vitro fertilization procedure. Sperm and an egg cell are mixed together on a glass dish.

After conception, the zygote (fertilised egg) is allowed to develop into a blastula (a hollow mass of cells). The zygote divides first into two cells, then four, then eight... A chemical is added to the dish to remove the "zona pellucida" covering. This material provides nutrients to the cells to promote cell division.

With the covering removed, the blastula is divided into individual cells which are deposited on individual dishes. They are then coated with an artificial "zona pellucida" and allowed to divide and develop. The experiment by 'Sill man et al'. showed that the best results could be obtained by interrupting the zygote at the two cell stage. Many of these pairs of zygotes were each able to develop to the 32 cell stage, but stalled at that point. They might well have had the potential to develop further and even mature into a viable fetus, except that the original ovum was defective and would have died anyway. For ethical reasons, the researchers had selected embryos which had no possibility of ever maturing into fetuses, and thus becoming newborn babies.

Reproductive Cloning Reproductive cloning is a technology used to generate an animal that has the same nuclear DNA as another currently or previously existing animal. Dolly was created by reproductive cloning technology. In a process called "somatic cell nuclear transfer" (SENT), scientists transfer genetic material from the nucleus of a donor adult cell to an egg whose nucleus, and thus its genetic material, has been removed. The reconstructed egg containing the DNA from a donor cell must be treated with chemicals or electric current in order to stimulate cell division. Once the cloned embryo reaches a suitable stage, it is transferred to the uterus of a female host where it continues to develop until birth. Dolly's success is truly remarkable because it proved that the genetic material from a specialized adult cell, such as an udder cell programmed to express only those genes needed by udder cells, could be reprogrammed to generate an entire new organism.

Before this demonstration, scientists believed that once a cell became specialized as a liver, heart, udder, bone, or any other type of cell, the change was permanent and other unneeded genes in the cell would become inactive. Some scientists believe that errors or incompleteness in the reprogramming process cause the high rates of death, deformity, and disability observed among animal clones. Procedure With the exception of the sperm and egg, every cell in the body contains all of the genetic material in its DNA to theoretically create an exact clone of the original body. But cells have been "biochemically programmed to perform limited functions". The other functions are turned off. Most scientists had believed that such differentiated cells could not be reprogrammed to be capable of behaving as a fertilized egg.

In the case of the sheep "Dolly", a cell was taken from the mammary tissue of a mature 6 year old sheep while its DNA was in a dormant state. It was fused with a sheep ovum which had had its nucleus removed. The "fertilized" cell was then stimulated with an electric pulse. (See Figure 3) Out of 277 attempts at cell fusion, only 29 began to divide. These were all implanted in ewes. Thirteen became pregnant but only one lamb, Dolly, was born.

Figure 3: The cloning process for the sheep "Dolly" Source: Available from URL: web (Accessed Thursday 12th August 2004) Therapeutic cloning This is a procedure whose initial stages are identical to adult DNA cloning. However, the stem cells are removed from the pre-embryo with the intent of producing tissue or a whole organ for transplant back into the person who supplied the DNA. The pre-embryo dies in the process. The goal of therapeutic cloning is to produce a healthy copy of a sick person's tissue or organ for transplant. This technique would be vastly superior to relying on organ transplants from other people. The supply would be unlimited, so there would be no waiting lists.

The tissue or organ would have the sick person's original DNA; the patient would not have to take immunosuppressant drugs for the rest of their life, as is now required after transplants. There would not be any danger of organ rejection. Figure 4: Human Therapeutic Cloning Source: Advanced Cell Technology, Inc. Worcester, Massachusetts, 2004, Human therapeutic cloning [online] Available form URL: web (Accessed Tuesday 17th August 2004) Procedure 1. Take a woman's ovum, and remove its DNA. This converts it to a form of human life into what is basically a factory for creating a pre-embryo.

2. Remove the DNA from a cell taken from a human, and inserting it into the ovum. 3. Giving the resulting ovum an electrical shock to start up its embryo making operation. In a small percentage of cases, a pre-embryo will be formed. 4.

The pre-embryo is allowed to develop and produce many stem cells. So far, the procedure is identical to that used in adult DNA cloning. However, the pre-embryo is not implanted in a woman's womb in order to try to produce a pregnancy. 5. Stem cells are removed from the pre-embryo; this results in its death. 6.

The stem cells would be encouraged to grow into whatever tissue or organ is needed to treat the patient. Stem cells are a unique form of human cell that can theoretically develop into many organs or body parts. 7. The tissue or organ would be transplanted into the patient. Benefits of Cloning There are many ways in which cloning is expected to benefit mankind.

Below is a list that is far from complete. Rejuvenation. Dr. Richard Seed, one of the leading proponents of human cloning technology, suggests that it may someday be possible to reverse the aging process because of what we learn from cloning. Human cloning technology could be used to reverse heart attacks. Scientists believe that they may be able to treat heart attack victims by cloning their healthy heart cells and injecting them into the areas of the heart that have been damaged. There has been a breakthrough with human stem cells.

Embryonic stem cells can be grown to produce organs or tissues to repair or replace damaged ones. Skin for burn victims, brain cells for the brain damaged, spinal cord cells for quadriplegics and paraplegics, hearts, lungs, livers, and kidneys could be produced. By combining this technology with human cloning technology it may be possible to produce needed tissue for suffering people that will be free of rejection by their immune systems. Conditions such as Alzheimer's disease, Parkinson's disease, diabetes, heart failure, degenerative joint disease, and other problems may be made curable if human cloning and its technology are not banned. Infertility. With cloning, infertile couples could have children.

Despite getting a fair amount of publicity in the news current treatments for infertility, in terms of percentages, are not very successful. One estimate is that current infertility treatments are less than 10 percent successful. Couples go through physically and emotionally painful procedures for a small chance of having children. Many couples run out of time and money without successfully having children.

Human cloning could make it possible for many more infertile couples to have children than ever before possible. Defective genes. The average person carries 8 defective genes inside them. These defective genes allow people to become sick when they would otherwise remain healthy. With human cloning and its technology it may be possible to ensure that we no longer suffer because of our defective genes. Down's syndrome.

Those women at high risk for Down's syndrome can avoid that risk by cloning. Leukemia. We should be able to clone the bone marrow for children and adults suffering from leukemia. This is expected to be one of the first benefits to come from cloning technology. Cancer. We may learn how to switch cells on and off through cloning and thus be able to cure cancer.

Scientists still do not know exactly how cells differentiate into specific kinds of tissue, nor do they understand why cancerous cells lose their differentiation. Cloning, at long last, may be the key to understanding differentiation and cancer. Cystic fibrosis. We may be able to produce effective genetic therapy against cystic fibrosis. Ian Wilmut and colleagues are already working on this problem. Testing for genetic disease.

Cloning technology can be used to test for and perhaps cure genetic diseases. The above list only scratches the surface of what human cloning technology can do for mankind. The suffering that can be relieved is staggering. This new technology heralds a new era of unparalleled advancement in medicine if people will release their fears and let the benefits begin.

Why should another child die from leukemia when if the technology is allowed we should be able to cure it in a few years time? Ethical Problems with Cloning Although there are benefits, many believe that cloning is unsafe to practise on human beings and that it poses serious risks to the developing clone and to the pregnant woman due to genetic abnormalities. These beliefs go as follows; The attempt to perfect human cloning despite the high risks of injury would constitute a violation of the fundamental principle of all human research: Do No Harm. To proceed on the basis that the eventual benefits may outweigh the probable harms to woman and child is not science... Efforts to create human beings by cloning shift human reproduction into a manufacturing process in which children are made in laboratories to pre-ordered specifications and in multiple copies. Any "functionally" deficient human clone will likely not be seen to warrant the same rights, freedoms, and protections as every other individual in society.

While people have indicated a desire to be cloned, almost no one has claimed that they would want to be a clone. Cloning could easily be used to reproduce living or deceased persons without their informed consent. Skin cells could be used from one's toothbrush or comb. Research cloning also raises serious issues related to women's health.

Therapeutic cloning will require 50-100 eggs to create enough cloned embryos just to develop a few stem cell lines. Donating eggs is an invasive procedure. Moreover, for women to donate their eggs, they need to take super ovulatory drugs, which have been linked to higher risks of ovarian cancer. But instead of facing these risks for the purpose of having a child, women will be asked to accept these risks to donate their eggs solely for money.

The prospect of creating new human life solely to be exploited and destroyed in this way has been condemned on moral grounds by many, including supporters of a right to abortion, as displaying a profound disrespect for life. Recent scientific advances indicate that there are fruitful and morally unproblematic alternatives to this approach, such as adult stem cell research. Adult stem cells have already been used successfully in clinical trials to treat cartilage defect in children, restore vision to patients who were legally blind, relieve systemic lupus, multiple sclerosis, and rheumatoid arthritis and cure severe combined immunodeficiency disease. Personal Viewpoint After analysing the advantages and disadvantages of cloning I have concluded that the practice of cloning can be used to benefit society overall and therefore should be legalized. Ever since the cloning of the first adult sheep, "Dolly", the idea of cloning has become a major issue and the subject of many debates.

Many people are afraid of the idea of cloning because it is new and misunderstood. There is the notion that a clone would not be the same as any other person, but a clone is just a normal person, created with and having the same genes as the person being cloned. A clone will not be exactly the same as the original person. Because they will not have the same environment and experiences as the person from which they were cloned, a clone is more like a younger identical twin with a personality all of its own.

There are also differences in mitochondria and uterine that makes the person different. Cloning is not that far from procedures that are being done all the time, such as in-vitro fertilization, where egg fertilization takes place in a lab and is then transferred to the uterus. In-vitro fertilization usually requires the retrieval of many cells and can take several times to work if it does at all. It can also result in multiple pregnancies. Cloning is only another alternative to reproduction and unlike IVF; it takes very few cells and should work the first time with a single pregnancy making it a more efficient method of reproduction. Some people argue against cloning because they think that it is a way of playing God.

But in reality, doctors 'play God' every day. It is commonly accepted that we create babies in test tubes and take birth control pills to prevent them, so why not clone them too? Today, many fetuses are screened for genetic or chromosomal abnormalities, with the option of abortion for those with defects. Is this not another way we 'play God', making decisions on whether or not this foetus will live based on whether or not it has a defect?

Why not go a step further and instead of eliminating the baby, make sure that there will be no defect to worry about. In addition, because there are many benefits to cloning and since not everyone believes in a God why should religion be used in making decisions for people where religious morality is not even an issue? The beliefs of some people should not deprive others of the benefits of cloning. There are those with religious beliefs who think that taking antibiotics or receiving blood transfusions is wrong, but this does not stop the rest of the world from receiving the benefits from them. This is just another tool that can be used to our advantage, so why not do it if it can help improve the health of society? Furthermore, because a human clone is and should be thought of as a regular human, they are entitled to have the same basic rights as everyone else.

There should not be the creation of entire embryos for the harvesting of parts because this goes against the rights of the clone and treats it as less than human. But, with new technology, scientists are finding ways to create entire separate organs and other tissues such as nerve or heart muscle cells without the creation of an entire person. These organs can be used for transplants and with scientists cloning organs from the own patients DNA there should be no problem with immune rejection that can result with transplants from other sources. There is a large shortage in the number of organs available for transplants and continued research in cloning of this type could eliminate this problem. But this may never come about if there are laws prohibiting cloning and its research. Another benefit of cloning is that it can give couples that cannot reproduce a chance to have children who are biologically related to them, whereas they otherwise could not.

This will also help those who are at a high risk for having a child with a genetic disease. They could clone one of themselves and have a healthy baby with their genes. This reproduction through cloning is close enough to other common reproduction and genetic-selection practices that it should not be treated any differently and given as an option. Going a step further, with germ-line engineering, defective genes could be eliminated in children and in their offspring, virtually eliminating many inherited diseases.

(See Figure 5) Some scientists believe that this could lead to the engineering of people completely resistant to other diseases, like AIDS and cancer, making society happier and healthier. Those who say that cloning and genetic engineering do not value human life are wrong because as you can see these processes can make life longer and better for many in our society. Figure 5: Germline Engineering Source: [online] Available form URL: web (Accessed: Thursday 19th August 2004) Animals are currently being cloned, like cattle and sheep that have been genetically engineered to maximize desirable traits. Research is also being done on the cloning of endangered species and dead animals. Many people do support cloning and whether the government makes laws against it or not, it will most likely take place.

In conclusion, whether Governments ban cloning or not, it is inevitably going to take place. The discovery and creation of the cloned sheep "Dolly" has made scientists all over the world curious and they are not just going to leave it alone. Decisions on whether or not your own DNA is replicated should be an issue that is private and left up to individuals, not the government. Although there are some negative aspects of cloning, I feel that the positive aspects and the large amounts of benefits people will receive from its use will be greatly appreciated by the World's population.

Available from URL: web (Accessed Sunday 22nd August 2004) Mitchell McIlwain

Bibliography

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