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เซลต้นกำเนิด 
   Stem Cells: A Primer
   - Definitions
     ศัพท์เกี่ยวกับเรื่องเซลและ
     ยีน การโคลนนิ่ง

  
- What is a stem cell?
    ความหมายเซลต้นแบบ
  -
 Introduction to Human
    Embryo Cloning

    เริ่มต้นกับการเริ่มโคลนนิ่ง
    ตัวอ่อนมนุษย์
 
- Why Clone Human 
    Embryos?

    เราคิดโคลนนิ่งตัวอ่อนมนุษย์
    ไปเพื่ออะไร
 
-To Clone or not to
   Clone:
   The Ethical Question

   เรื่องปัญหาจริยธรรมว่าการ
   โคลนนิ่งดีหรือไม่

การโคลนตัวอ่อนมนุษย์เพื่อ
    การศึกษารูปแบบการนำเอา
    เซลต้นแบบมาใช้ในการรักษา
    ทางการแพทย์

    Using cloned human 
    embryos for research




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  เซลต้นกำเนิด Stem Cells: A Primer

 
This primer presents background information on stem cells. It includes an explanation of what stem cells are; what pluripotent stem cells are; how pluripotent stem cells are derived; why pluripotent stem cells are important to science; why they hold such great promise for advances in health care; and what adult stem cells are.

Recent published reports on the isolation and successful culturing of the first human pluripotent stem cell lines have generated great excitement and have brought biomedical research to the edge of a new frontier. The development of these human pluripotent stem cell lines deserves close scientific examination, evaluation of the promise for new therapies, and prevention strategies, and open discussion of the ethical issues.
In order to understand the importance of this discovery as well as the related scientific, medical, and ethical issues, it is absolutely essential to first clarify the terms and definitions.

 

Definitions

DNA - abbreviation for deoxyribonucleic acid which makes up genes.

Gene - a functional unit of heredity which is a segment of DNA located in a specific site on a chromosome. A gene directs the formation of an enzyme or other protein.

Somatic cell - cell of the body other than egg or sperm.

Somatic cell nuclear transfer - the transfer of a cell nucleus from a somatic cell into an egg from which the nucleus has been removed.

Stem cells - cells that have the ability to divide for indefinite periods in culture and to give rise to specialized cells.

Pluripotent -capable of giving rise to most tissues of an organism.

Totipotent - having unlimited capability. Totipotent cells have the capacity to specialize into extraembryonic membranes and tissues, the embryo, and all postembryonic tissues and organs.

 

What is a stem cell?

Stem cells have the ability to divide for indefinite periods in culture and to give rise to specialized cells. They are best described in the context of normal human development. Human development begins when a sperm fertilizes an egg and creates a single cell that has the potential to form an entire organism. This fertilized egg is totipotent, meaning that its potential is total. In the first hours after fertilization, this cell divides into identical totipotent cells. (Figure I) This means that either one of these cells, if placed into a woman's uterus, has the potential to develop into a fetus. In fact, identical twins develop when two totipotent cells separate and develop into two individual, genetically identical human beings. Approximately four days after fertilization and after several cycles of cell division, these totipotent cells begin to specialize, forming a hollow sphere of cells, called a blastocyst. The blastocyst has an outer layer of cells and inside the hollow sphere, there is a cluster of cells called the inner cell mass.

The outer layer of cells will go on to form the placenta and other supporting tissues needed for fetal development in the uterus. The inner cell mass cells will go on to form virtually all of the tissues of the human body. Although the inner cell mass cells can form virtually every type of cell found in the human body, they cannot form an organism because they are unable to give rise to the placenta and supporting tissues necessary for development in the human uterus. These inner cell mass cells are pluripotent — they can give rise to many types of cells but not all types of cells necessary for fetal development. Because their potential is not total, they are not totipotent and they are not embryos. In fact, if an inner cell mass cell were placed into a woman's uterus, it would not develop into a fetus.

The pluripotent stem cells undergo further specialization into stem cells that are committed to give rise to cells that have a particular function. Examples of this include blood stem cells which give rise to red blood cells, white blood cells and platelets; and skin stem cells that give rise to the various types of skin cells. These more specialized stem cells are called multipotent. (Figure II)

While stem cells are extraordinarily important in early human development, multipotent stem cells are also found in children and adults. For example, consider one of the best understood stem cells, the blood stem cell. Blood stem cells reside in the bone marrow of every child and adult, and in fact, they can be found in very small numbers circulating in the blood stream. Blood stem cells perform the critical role of continually replenishing our supply of blood cells — red blood cells, white blood cells, and platelets — throughout life. A person cannot survive without blood stem cells.

How are pluripotent stem cells derived?

At present, human pluripotent cell lines have been developed from two sources1 with methods previously developed in work with animal models.

(1) In the work done by Dr. Thomson, pluripotent stem cells were isolated directly from the inner cell mass of human embryos at the blastocyst stage. Dr. Thomson received embryos from IVF (In Vitro Fertilization) clinics-these embryos were in excess of the clinical need for infertility treatment. The embryos were made for purposes of reproduction, not research. Informed consent was obtained from the donor couples. Dr. Thomson isolated the inner cell mass (see Figure III) and cultured these cells producing a pluripotent stem cell line.

(2) In contrast, Dr. Gearhart isolated pluripotent stem cells from fetal tissue obtained from terminated pregnancies. Informed consent was obtained from the donors after they had independently made the decision to terminate their pregnancy. Dr. Gearhart took cells from the region of the fetus that was destined to develop into the testes or the ovaries. Although the cells developed in Dr. Gearhart's lab and Dr. Thomson's lab were derived from different sources, they appear to be very similar. (Figure III)

The use of somatic cell nuclear transfer (SCNT) may be another way that pluripotent stem cells could be isolated. In studies with animals using SCNT, researchers take a normal animal egg cell and remove the nucleus (cell structure containing the chromosomes). The material left behind in the egg cell contains nutrients and other energy-producing materials that are essential for embryo development. Then, using carefully worked out laboratory conditions, a somatic cell - any cell other than an egg or a sperm cell - is placed next to the egg from which the nucleus had been removed, and the two are fused. The resulting fused cell, and its immediate descendants, are believed to have the full potential to develop into an entire animal, and hence are totipotent. As described in Figure I, these totipotent cells will soon form a blastocyst. Cells from the inner cell mass of this blastocyst could, in theory, be used to develop pluripotent stem cell lines. Indeed, any method by which a human blastocyst is formed could potentially serve as a source of human pluripotent stem cells (Figure IV).

Potential Applications of Pluripotent Stem Cells

There are several important reasons why the isolation of human pluripotent stem cells is important to science and to advances in health care (Figure V). At the most fundamental level, pluripotent stem cells could help us to understand the complex events that occur during human development. A primary goal of this work would be the identification of the factors involved in the cellular decision-making process that results in cell specialization. We know that turning genes on and off is central to this process, but we do not know much about these "decision-making" genes or what turns them on or off. Some of our most serious medical conditions, such as cancer and birth defects, are due to abnormal cell specialization and cell division. A better understanding of normal cell processes will allow us to further delineate the fundamental errors that cause these often deadly illnesses.

Human pluripotent stem cell research could also dramatically change the way we develop drugs and test them for safety. For example, new medications could be initially tested using human cell lines. Cell lines are currently used in this way (for example cancer cells). Pluripotent stem cells would allow testing in more cell types. This would not replace testing in whole animals and testing in human beings, but it would streamline the process of drug development. Only the drugs that are both safe and appear to have a beneficial effect in cell line testing would graduate to further testing in laboratory animals and human subjects.

Perhaps the most far-reaching potential application of human pluripotent stem cells is the generation of cells and tissue that could be used for so-called "cell therapies." Many diseases and disorders result from disruption of cellular function or destruction of tissues of the body. Today, donated organs and tissues are often used to replace ailing or destroyed tissue. Unfortunately, the number of people suffering from these disorders far outstrips the number of organs available for transplantation. Pluripotent stem cells, stimulated to develop into specialized cells, offer the possibility of a renewable source of replacement cells and tissue to treat a myriad of diseases, conditions, and disabilities including Parkinson's and Alzheimer's diseases, spinal cord injury, stroke, burns, heart disease, diabetes, osteoarthritis and rheumatoid arthritis. There is almost no realm of medicine that might not be touched by this innovation. Some details of two of these examples follow.

 

  • Transplant of healthy heart muscle cells could provide new hope for patients with chronic heart disease whose hearts can no longer pump adequately. The hope is to develop heart muscle cells from human pluripotent stem cells and transplant them into the failing heart muscle in order to augment the function of the failing heart. Preliminary work in mice and other animals has demonstrated that healthy heart muscle cells transplanted into the heart successfully repopulate the heart tissue and work together with the host cells. These experiments show that this type of transplantation is feasible.

     

  • In the many individuals who suffer from Type I diabetes, the production of insulin by specialized pancreatic cells, called islet cells, is disrupted. There is evidence that transplantation of either the entire pancreas or isolated islet cells could mitigate the need for insulin injections. Islet cell lines derived from human pluripotent stem cells could be used for diabetes research and, ultimately, for transplantation.

While this research shows extraordinary promise, there is much to be done before we can realize these innovations. Technological challenges remain before these discoveries can be incorporated into clinical practice. These challenges, though significant, are not insurmountable.

First, we must do the basic research to understand the cellular events that lead to cell specialization in the human, so that we can direct these pluripotent stem cells to become the type(s) of tissue needed for transplantation.

Second, before we can use these cells for transplantation, we must overcome the well-known problem of immune rejection. Because human pluripotent stem cells derived from embryos or fetal tissue would be genetically different from the recipient, future research would need to focus on modifying human pluripotent stem cells to minimize tissue incompatibility or to create tissue banks with the most common tissue-type profiles.

The use of somatic cell nuclear transfer (SCNT) would be another way to overcome the problem of tissue incompatibility for some patients. For example, consider a person with progressive heart failure. Using SCNT, the nucleus of virtually any somatic cell from that patient could be fused with a donor egg cell from which the nucleus had been removed. With proper stimulation the cell would develop into a blastocyst: cells from the inner cell mass could be taken to create a culture of pluripotent cells. These cells could then be stimulated to develop into heart muscle cells. Because the vast majority of genetic information is contained in the nucleus, these cells would be essentially identical genetically to the person with the failing heart. When these heart muscle cells were transplanted back into the patient, there would likely be no rejection and no need to expose the patient to immune-suppressing drugs, which can have toxic effects.

Adult Stem Cells

As noted earlier, multipotent stem cells can be found in some types of adult tissue. In fact, stem cells are needed to replenish the supply cells in our body that normally wear out. An example, which was mentioned previously, is the blood stem cell.

Multipotent stem cells have not been found for all types of adult tissue, but discoveries in this area of research are increasing. For example, until recently, it was thought that stem cells were not present in the adult nervous system, but, in recent years, neuronal stem cells have been isolated from the rat and mouse nervous systems. The experience in humans is more limited. In humans, neuronal stem cells have been isolated from fetal tissue and a kind of cell that may be a neuronal stem cell has been isolated from adult brain tissue that was surgically removed for the treatment of epilepsy.

Do adult stem cells have the same potential as pluripotent stem cells?

Until recently, there was little evidence in mammals that multipotent cells such as blood stem cells could change course and produce skin cells, liver cells or any cell other than a blood stem cell or a specific type of blood cell; however, research in animals is leading scientists to question this view.

In animals, it has been shown that some adult stem cells previously thought to be committed to the development of one line of specialized cells are able to develop into other types of specialized cells. For example, recent experiments in mice suggest that when neural stem cells were placed into the bone marrow, they appeared to produce a variety of blood cell types. In addition, studies with rats have indicated that stem cells found in the bone marrow were able to produce liver cells. These exciting findings suggest that even after a stem cell has begun to specialize, the stem cell may, under certain conditions, be more flexible than first thought. At this time, demonstration of the flexibility of adult stem cells has been only observed in animals and limited to a few tissue types.

Why not just pursue research with adult stem cells?

Research on human adult stem cells suggests that these multipotent cells have great potential for use in both research and in the development of cell therapies. For example, there would be many advantages to using adult stem cells for transplantation. If we could isolate the adult stem cells from a patient, coax them to divide and direct their specialization and then transplant them back into the patient, it is unlikely that such cells would be rejected. The use of adult stem cells for such cell therapies would certainly reduce or even avoid the practice of using stem cells that were derived from human embryos or human fetal tissue, sources that trouble many people on ethical grounds.

While adult stem cells hold real promise, there are some significant limitations to what we may or may not be able to accomplish with them. First of all, stem cells from adults have not been isolated for all tissues of the body. Although many different kinds of multipotent stem cells have been identified, adult stem cells for all cell and tissue types have not yet been found in the adult human. For example, we have not located adult cardiac stem cells or adult pancreatic islet stem cells in humans.

Secondly, adult stem cells are often present in only minute quantities, are difficult to isolate and purify, and their numbers may decrease with age. For example, brain cells from adults that may be neuronal stem cells have only been obtained by removing a portion of the brain of epileptics, not a trivial procedure.

Any attempt to use stem cells from a patient's own body for treatment would require that stem cells would first have to be isolated from the patient and then grown in culture in sufficient numbers to obtain adequate quantities for treatment. For some acute disorders, there may not be enough time to grow enough cells to use for treatment. In other disorders, caused by a genetic defect, the genetic error would likely be present in the patient's stem cells. Cells from such a patient may not be appropriate for transplantation. There is evidence that stem cells from adults may have not have the same capacity to proliferate as younger cells do. In addition, adult stem cells may contain more DNA abnormalities, caused by exposure to daily living, including sunlight, toxins, and by expected errors made in DNA replication during the course of a lifetime. These potential weaknesses could limit the usefulness of adult stem cells.

Research on the early stages of cell specialization may not be possible with adult stem cells since they appear to be farther along the specialization pathway than pluripotent stem cells. In addition, one adult stem cell line may be able to form several, perhaps 3 or 4, tissue types, but there is no clear evidence that stem cells from adults, human or animal, are pluripotent. In fact, there is no evidence that adult stem cells have the broad potential characteristic of pluripotent stem cells. In order to determine the very best source of many of the specialized cells and tissues of the body for new treatments and even cures, it will be vitally important to study the developmental potential of adult stem cells and compare it to that of pluripotent stem cells.

Summary

Given the enormous promise of stem cells to the development of new therapies for the most devastating diseases, it is important to simultaneously pursue all lines of research. Science and scientists need to search for the very best sources of these cells. When they are identified, regardless of their sources, researchers will use them to pursue the development of new cell therapies.

The development of stem cell lines, both pluripotent and multipotent, that may produce many tissues of the human body is an important scientific breakthrough. It is not too unrealistic to say that this research has the potential to revolutionize the practice of medicine and improve the quality and length of life.

 


1 Michael Shamblott, et al, Derivation of pluripotent stem cells from cultured human primordial germ cells. PNAS, 95: 13726-13731, Nov. 1998.

James Thomson, et al, Embryonic stem cell lines derived from human blastocysts. Science, 282: 1145-1147, Nov. 6, 1998.

 

โคลนนิ่งหรือสำเนามนุษย์ เป็นผลงานแสดงความก้าวหน้าของวิศวกรรมพันธุศาสตร์ ซึ่งทั่วโลกประนาม และไม่ยินยอมให้พัฒนา เพราะเข้าใจถึงพิษภัยของมนุษยชาติ ขณะนี้การศึกษา DNA ทั้งระบบ ก็กำลังกลัวเกรงถึงผลกระทบที่จะตามมา ประโยชน์ทางการแพทย์นั้นมีมากมายมหาศาลทั้งในเชิงป้องกัน และการรักษาโรค แต่ผลกระทบทางสังคมนั้นก็น่ากลัวมาก คนจะตกงานเพิ่มมากขึ้น เสถียรภาพทางสังคมจะถูกกระทบ เพราะเมื่อมนุษย์ทุกคนสามารถทราบถึงพิมพ์เขียวชีวิต ของตัวเองว่ามีหน่วยพันธุกรรมที่บกพร่องอย่างไร การว่าจ้างเข้าทำงานก็จะถูกปฏิเสธ ถ้านายจ้างทราบว่ามีหน่วยพันธุกรรม ที่ส่อแสดงว่าจะมีโรคเรื้อรังหรือโรคร้าย ซึ่งจะทำให้ทางบริษัทต้องสั่งเปลี่ยนงบประมาณในการรักษาพยาบาลแก่ผู้นั้นเมื่อรับเข้าทำงาน ไม่เท่านั้นการประกันชีวิต การประกันภัย ประกันสุขภาพ บุคคลเหล่านี้ก็จะถูกบริษัทประกันปฏิเสธ เพราะมีแนวโน้มที่ทางบริษัทประกัน จะต้องจ่ายเงินให้จำนวนมาก

บุคคลนั้นก็จะไม่มีหลักประกันทางสังคม ถ้าเกิดการทำแมพพิ่งตั้งแต่เยาว์วัยก็มีสิทธิ์ที่จะขึ้นคาน เพราะไม่มีใครอยากจะอยู่กับคนที่มีอนาคตเป็นโรคเรื้อรัง มนุษย์คงจะใกล้เคียงกับเครื่องจักร ไม่มีศักดิ์ศรีของความเป็นมนุษย์เหลืออยู่เท่าใด เพราะจะทราบอายุใช้งานของตัวเอง คงมีแต่ความท้อถอยหดหู่ เพราะรู้อนาคตว่าจะต้องผจญกับโรคอะไรบ้าง อาจจะมีโรงงานทำลายมนุษย์ก่อนที่จะเกิดโรค หรือมีโรงงานที่ให้มนุษย์เข้ามารับการเปลี่ยนอะไหล่ คล้ายเครื่องยนต์พอหมดอายุใช้งานก็เปลี่ยนอุปกรณ์ หรือถ้าเห็นจะหนักก็เข้าป่าช้ารถยนต์เพื่อทำลาย แล้วนำไปหลอมใหม่ แต่มนุษย์ก็ทำในลักษณะเดียวกันได้ คือ เก็บเอาหน่วยพันธุกรรม ไว้ในนิวเคลียสไปทำโคลนนิ่ง หรือสำเนามนุษย์ขึ้นมาใหม่ ขณะนี้นักวิทยาศาสตร์กำลังทำแผนที่พันธุกรรมมนุษย์ให้ก้าวหน้าไปเรื่อย ๆ เมื่อเสร็จครบแล้ว และสามารถจะพัฒนาระบบตรวจสอบขึ้นมาได้ มนุษย์ทุกคนก็สามารถจะรู้อนาคตในบางลักษณะได้ สังคมมนุษย์จะต้องมีการเปลี่ยนแปลงอย่างมโหฬารกันเลยทีเดียว

 

Human Cloning
Amina Ali and Owen Wood
CBC News Online, March 2001



Dolly, the world's most famous clone
I
n March 2001, three scientists gathered in Rome to say they're going ahead with human cloning, no matter what anyone says.

Their intentions seem good – they want to help infertile couples have children.

"Some people say we are going to clone the world, but this isn't true," Italian Severino Antinori, one of the doctors, said at a news conference. "We're talking science, we're not here to create a fuss."

The team plans to combine cells (from either the man or the woman) with one of the woman's eggs, which has been stripped of its genetic material. When the cells form an embryo, the scientists would implant the embryo in the woman's uterus. The embryo would then take its "natural" course and develop into a fetus and then a baby – a baby that would have only one biological parent.

 

Oregon scientists cloned a monkey
T
he idea that we may one day clone a human being
has been a part of science fiction and scientific debate for generations.

However, it wasn't until 1997, when a team in Scotland announced it had cloned the first adult mammal, the now-famous Dolly the sheep, that the world really changed the way it thought about human cloning. Those who were previously asking whether it could be done were now asking when it would be done.

But there's still the question of whether it should be done. And the ethical issues that surround human cloning can be as complicated as the science itself.

 

Sweater knit from cloned Dolly's wool
On the one side, there are religious groups and other organizations that say human cloning is wrong. Period.

Some are against cloning for the same reason they're against abortion and euthenasia – because all human life is valuable and destroying embryos is equal to murder. (Some scientists want to use embryos in medical research because they contain what are called "stem cells." Stem cells are cells that haven't matured to perform specialized functions, which means they still can be programmed to do anything, perfect for cloning.)

This is just one of the arguments.

There are also those anti-cloning advocates who say we shouldn't allow human cloning because it infringes on one of the things we value most, our individuality.

 

Einsteins for all?
There are social implications, too. What if someone 
cloned Albert Einstein or Joan of Arc or even someone they knew, like their dead child or parent? What kind of life would that person have trying to live up to the expectation that they will become as accomplished or do the same things as their genetic counterpart?

And then there are those who say allowing cloning would make way for the Frankenstein-like eugenics projects or the vast armies of genetically engineered soldiers that you see in the movies or read about in comic books.

This is not to say these arguments should be taken lightly. In fact, the international community has taken human cloning very seriously. Of those countries that have adopted laws to deal with reproductive technologies, the majority – France, Germany and Australia for example – have chosen to outlaw human cloning altogether to avoid such disasters.

The United States was one of the first to react to the Dolly announcement with President Bill Clinton banning the use of federal funds for human cloning research. The U.S. still has no national law to prevent private companies from doing such work, though it is illegal in some states.

 

Pigs have also been succesfully cloned
Canada has no cloning laws either.

Cloning laws would fall under the same act that would cover other reproductive technologies, such as in vitro fertilization, sperm donation and genetic manipulation.

In 1989, the federal government created a Royal Commission to look at new reproductive technologies, which resulted in the government placing a voluntary moratorium on human embryo cloning. But so far, attempts to pass an anti-cloning law have failed.

That's partly because of who makes up the other side the argument: the scientists who say we shouldn't be so quick to dismiss the benefits of human cloning.

Human cloning doesn't necessarily mean duplicating entire people. It also includes cloning parts of humans, cells, for example, that would no doubt be a great boost to medical science.

People with severe burns could grow back their own skin. People who need a new organ could get one that's guaranteed to be genetically compatible. And what about growing entire new limbs to replace those that have been severed in an accident?

The potential for human cloning is so great, scientists say it would be premature to stop research now, especially seeing as the world is just beginning to understand the possible applications of the technology.

This is why Britain, which had earlier passed a law banning human cloning, announced in January 2001 that it would now allow scientists to clone human embryos for medical research. The embryos must be destroyed by the time they are 14 days old, before the cells begin to change and form specific parts of the body.

In December 1998, scientists at the Infertility Clinic at Kyeonghee University in South Korea announced they had cloned the world's first human embryo. The team allowed the embryo to divide itself into four cells, the stage when a test tube embryo is usually placed back in the uterus where it develops into a fetus, before destroying it. Their goal is to clone genetically identical organs for human transplant.

 

Britain destroys human embryos after 14 days
N
o matter what governments do to prevent human 
cloning, and no matter what position you take on the issue, it's hard to ignore the reality that there are already people out there trying to be the first to clone a human being.

One group working in the field is the Bahamas-based Clonaid, the self-proclaimed "first human cloning company," that says it has both the technological and financial resources to clone a human being, and is already going ahead with trials.

The work is being done under a veil of secrecy. Clonaid hasn't released the name of the couple who want to clone their child – who died when she was 10 months old – and it also won't say where the cloning will be done other than that it will be in a U.S. state where cloning is still legal. The group wants to avoid demonstrations or possible violence by anti-cloning groups.

When Clonaid announced its intentions in October 2000, Dr. Brigitte Boisselier, a representative of the group, said they expected to have the first cloned baby within 18 months, which would be some time in the spring of 2002.

 

 

 

How to Clone a Human (Version 1.1)

This is not a joke procedure, it's the real thing. I have other pages for humor, but this page is only for serious cloning info. This page was updated on 2/27/98 (to version 1.1) with new information from Dr. Lee Silver of Princeton University, a noted expert on cloning. This procedure is based upon the Sheep cloning procedure. The mouse cloning procedure seems to have worked better, so I'll be changing this page to Version 1.2 when I get all that information together. The two procedures are similar, but not identical. This page provided courtesy of:

The BioFact Report

Materials

  • Human Tissue: Pure human cells of one tissue type, from the individual who will be cloned.
  • Human Tissue Culture Media: Media in which these human cells will grow and divide.
  • Minimal Human Tissue Culture Media: Media in which cells will stop dividing, and enter a state of "quiescence" without dying.
  • Laboratory supplies: Incubator, Sterile Hood, petri dishes, microscopes, and tools capable of removing and implanting cellular organelles, such as the nucleus, from one cell to another.
  • Unfertilized human egg cells.
  • Human Egg Cell growth media: Media where fertilized eggs will grow and divide.

Procedures

  1. Grow the human cells to be cloned until you have a good supply.
  2. Transfer the cells to minimal media. [For now, The Sheep Cloning Paper is a good reference for exactly how long.] This should allow the cells to live, but they should stop dividing and enter quiescence. This is likely the step in which the cells lose their differentiation, and revert to a more totipotent state.
  3. When the cultured cells are in the quiescent state, get an unfertilized human egg cell. Remove the nucleus from this egg cell. Try to minimize damage done to this cell and discard the nucleus.
  4. Take one of the quiescent cells in it's entirely, and implant it inside the coat around the egg (known as the zona pellucida) next to the egg itself.
  5. Electroshock the egg. [For now, The Sheep Cloning Paper is probably a good reference for how much and how long to electroshock.] The electroshock induces the fusion of the two cells, so you should be able to tell when you've electroshocked enough just by looking at the cells. The rebooting of the human genetic program is believed to be initiated by the replacement of donor cell protien signals by egg cell protien signals, but the electroshock might assist in moving those protien signals across the nuclear membrane as well. Electroporation is a common technique for moving DNA molecules through a cellular membrane.
  6. Repeat the last three steps as necessary until you have enough clones. Expect a lot of them not to survive because of cellular damage and other mishaps. Allow the embryos to grow and divide a few times in Human Egg Cell growth media.
  7. Implant the embryos in human mothers where they will can be carried to term, and born normally.

The content of this page is solely the responsibility of Arthur Kerschen.

 

 

Introduction to Human Embryo Cloning


INTRODUCTION

Research in the field of embryology and genetics has exploded over the past decade. New advances in in vitro fertilization and genetic screening are leading to new procedures in which human embryo cloning will be possible in the near future. Human cloning, however, brings up many new ethical questions that will need to be addressed by the scientific community and the public before these advances can reach their full potential. Scientific advances bring social changes, that many people will not be able to accept. As with any scientific or technological advance, the most important question that needs to be asked is whether or not the gains out weigh the potential losses. Will human cloning become a brave new step in fighting disease and improving the quality of life, or will it lead to dehumanization and a new genetic underclass?

 

HUMAN CLONING TECHNIQUES

The procedures used in cloning human embryos are very similar to the cloning of animal embryos, except for the zona pellucida. Several sperm cells and mature egg cells are gathered from donors at fertility clinics, and are combined in a petri dish using in vitro fertilization procedures to form an embryo. In an alternate process, already produced embryos are gathered from fertility clinics that have embryos left over from prior in vitro clients. The acquired embryo is placed in a petri dish and is allowed to develop into a mass of two to eight cells. Next, a chemical solution is added that dissolves the zona pellucida that covers the embryo. The zona pellucida is a protective protein and polysaccharide membrane that covers the internal contents of the embryo, and provides the necessary nutrients for the first several cell divisions that occur within the embryo. After the zona pellucida is dissolved the cells within the embryo are freed. These two to eight cells are then collected by the researchers and placed in separate petri dishes. These embryonic cells are called blastomeres, or cells that are a part of the hollow ball of cells know as the blastula: (Hale 83). The embryonic cells are then each coated with an artificially produced zona pellucida: (Fackelmann 276). The individual cells then are considered new embryos, all of which share the same exact genetic information. In effect at this point the science has produced multiple copies of life that could have never before existed. Do we as a society have the moral wisdom to determine the direction or understand the implications that this science provides our species? These cells will divide and will eventually form a human being, if allows to develop: (Fackelmann 276). Hall and Stillman's attempt to produce human embryo clones was only somewhat successful. The embryos that they used in their experiments were not able to produce human beings, because they were double fertilized, that is fertilized by more than one sperm cell. These embryos will eventually die during sometime in their development because of the extra set of chromosomes donated by the second sperm cell. The researchers removed two or more embryonic cells from seventeen different abnormal embryos, and allowed these cells (blastomeres) to develop into new individual embryos, using the above stated steps. These new embryos grew and divided at the anticipated rate, however, all eventually died before reaching the 64 cell stage. As was stated before, from two to eight embryonic cells may be removed from the original embryo, depending on the development of the embryo, but the experiments completed by Hall and Stillman showed that the best results were obtained from embryos that had divided only twice. These new embryos reached the 32 cell stage, whereas other original embryos of four or more cells, barely made it to the 16 cell stage. It is not known whether these new cloned embryos would have developed further if they had not been abnormal. Hall believes that the embryos might have developed even further in the more natural environment of the uterus: (Kolberg 652).


Why Clone Human Embryos?


REASONS FOR EMBRYO RESEARCH

Some people may think that biologists are cloning human embryos only to see how far they can push the scientific envelope, but there are many legitimate reasons for investigating cloning. Embryologists believe that research into cloning could help improve the life of future generations. I believe that this is the main concern of most scientists. Many biologists believe that they have a personal duty to the improvement of society, perhaps even a moral obligation. To this end the techniques of embryonic cloning and alteration have been offered to society as an option for the improvement of humanity. Doctors hope that by being able to study the multiple embryos developed through cloning, they can determine the causes of spontaneous abortions. Contraceptive specialists believe that if they can determine how an embryo knows where to implant itself, they can develop a contraceptive that would prevent embryos from implanting in the uterus: (Watson 66). Cancer research is possibly the most important reason for embryo cloning. Oncologists believe that embryonic study will advance understanding of the rapid cell growth of cancer. Cancer cells develop at approximately the same phenomenal speed as embryonic cells do. By studying the embryonic cell growth, scientists may be able to determine how to stop it, and also stop cancer growth in turn: (Watson 66). Another important area of embryo cloning research is embryonic stem cell development. Stem cells are undifferentiated cells that can develop into almost any type of cell in the body. These cells are not attacked by a persons immune system, because of their fast development and undifferentiated status. Many doctors believe that these stem cells could be used in treatments for brain and nervous system damage. In adult humans, when damage to nerve tissue takes place, the nerve tissue does not regenerate and replace the lost tissue. However, since the stem cells are undifferentiated they could theoretically be used to replace the damaged cells. Human embryo cloning is needed for the implantation of stem cells, because of the large amount of cells that would be needed: (Marshall 1026). Genetic screening is a branch of cloning research that is already being used in hospitals in England. Parents who have a history of genetically inherited disease, such as cystic fibrosis, can use embryo screening to determine if their child has received the defective gene. Several embryos can be developed via in vitro fertilization procedures, and then be cloned. The DNA from one of the cloned embryos would then be removed and standard genetic testing, using riflips, would be used to detect whether or not that embryo contained the genetic disease. If the cloned embryo does not contain the defective gene, then one of the other identical embryos can be used for implantation in the parent. This would almost guarantee that the child would be free of the genetic disease: (Marshall 1025). Perhaps a more questionable use of cloned embryos is for spare parts. It is possible that parents could decide to use one cloned embryo for implantation and eventual birth of a child, and save any spares by freezing them. If the child were to become critically sick, and need a bone marrow transplant, one of the frozen embryos could be thawed and implanted into the uterine wall for development of another identical child. The bone marrow from this child could then be used to help save the life of the child, perhaps even without the necessity of carrying the child to full term: (Cloning 1117). This again raises the question of what moral status a fetus should have, if any at all?

 

Ethical Concerns

FEDERAL GUIDELINES FOR HUMAN EMBRYO CLONING

Because human embryo research is just in its infancy, there has been a rush to decide what guidelines are going to be instituted for governing cloning experiments. To assist the National Institutes of Health (NIH) in determining which cloning experiments to fund, a medical panel was set up to form a preliminary set of guidelines. Steven Muller, the head of the panel, set out with the help of several prominent biologists including, Brigid Hogan and embryology specialist Mark Hughes, to put together a set of guidelines that would satisfy the concerns of both the scientific and religious communities. The religious community vigorously opposes all human cloning procedures. The scientific community sympathizes with the religious communities concerns, but does not want to lose the enormous amount of information that may be gained by human embryo cloning. Muller's panel announced a set of guidelines that they hope would be acceptable to both communities. They recommended research be permitted on preexisting embryos. These embryos would be allowed to develop up to and including the fourteenth day. Researchers would also be allowed to produce new embryos only for what the NIH considers "compelling research." Researchers would also be permitted to remove some of the embryonic cells from embryos that are destined for in vitro fertilization at a later time: (Marshall 1024). The panel did not come to a decision in several other areas of research funding. Research on fetal oocytes and research on embryos whose donator is unavailable to give consent were left undecided. This brings up a question as to whether or not a person who aborts a fetus still has parental rights pertaining to that fetus. Legally the aborted fetus is not a person and has no legal status. Society needs to decide whether or not the fetus has a moral status. The panel suggested that research might be permitted after the fourteenth day of development depending on the circumstances, but definitely not after the eighteenth day, when neural tube closure begins. The neural tube is the beginning of the nervous system, including the brain, in adult humans: (Marshall 1024). Thus the scientific community seems to be giving more moral consideration to an embryo then a majority of society gives to a more developed fetus. The experiments that the panel recommended be banned include impregnating human embryos in other animal species, impregnating cloned embryos into humans, the use of embryos for sex selection, or the transfer of one nucleus from one embryo to another. These are but a few of the procedures that the panel felt were inappropriate for federal funding: (Marshall 1024). I want to be clear on this fact: the above limitations only apply to federally funded experiments. Currently there are no laws directly prohibiting any of the above procedures in private research settings. It should also be stated that all of the above procedures have or can be carried out with current technology.

 

Lets Wrap it Up!

CONCLUSION

Human embryo cloning obviously is a great source for human advancement, and will more than likely help millions of people world wide, but we must never overlook the possible harm that it could cause as well. The United States will probably never allow many of the more radical uses of human embryo clones, especially for screening superficial traits, but there are countries in the world that might not think twice about the ethical concerns. Ethnic cleansing is occurring in many places around the world today, and embryo screening and cloning maybe just another tool in their arsenal. Robert Stillman probably did the best thing any scientist could ever do by shocking the world to what lies ahead. As with any scientific or technological advance the most important question that needs to be asked, is whether or not the gains out weigh the potential losses?

 

 

Joseph Farnsworth
April 7, 2000
         
  
A couple that had been married for only two years was in a terrible car accident.   The wife walked away with a few cuts and bruises.  The husband, however was unconscious when the paramedics arrived.  He went into a coma shortly after arriving at the nearby hospital. He came out of the coma but was never to be the same again.  It turns out that when he was in the accident he had severe head trauma, and would be a vegetable the rest of his life.  He could not take part in the reproduction of children.  The wife is now distraught because they will never have children together.  She heard about the possibility of cloning and believes that it is the only way that she will ever have children.  Is it so?

Introduction
The ethics of human cloning has become a great issue in the past few years.  The advocates for both sides of the issue have many reasons to clone or not to clone.  This is an attempt to explore the pros and cons of human cloning and to provide enough information of both sides of the arguments in order for the reader to make their own informed decision on whether human cloning is ethical or not.  Cloning will first be defined.  Then a brief explanation of why questions concerning cloning humans have arisen will be presented.  Some things cannot be known for sure unless it is tested, i.e., human cloning is allowed. Followed by that, a discussion of the facts and opinions that support cloning will be presented and then the same against cloning.  Please remember that not all of this has proven true nor is able to be proven yet, but has simply been argued as a scientific hypothesis.  Finally, my own personal opinion will be stated.

  
Defining Human Cloning
When speaking of human cloning, what is meant?  Different groups and organizations define it differently.  To use a specific definition, the American Medical Association (AMA) defined cloning as “the production of genetically identical organisms via somatic cell nuclear transfer.  ‘Somatic cell nuclear transfer’ refers to the process which the nucleus of a somatic cell of an existing organism is transferred into an oocyte from which the nucleus has been removed” (Council on Ethical and Judicial Affairs 1).  In other words, cloning is the method of produce a baby that has the same genes as its parent.  You take an egg and remove its nucleus, which contains the DNA/genes.  Then you take the DNA from an adult cell and insert it into the egg, either by fusing the adult cell with the enucleated egg, or by a sophisticated nuclear transfer.  You then stimulate the reconstructed egg electrically or chemically and try to make it start to divide and become an embryo.  You then use the same process to implant the egg into a surrogate mother that you would use with artificial insemination.  (Eibert)

However, many groups have used a broader definition of cloning.  They include the production of tissues and organs through growing cells or tissues in cultures along with the actual producing of embryos to be born.  This is done with the use of stem cells.  When an egg is fertilized and begins to divide, the cells are all alike.  As the cells divide, certain cells differentiate and become the stem cells that produce certain tissue and then organs.  Research in this very active.  There is still much for scientists to learn about cell differentiation and how it works.  To a clone an organ, a stem cell must be produced and then used to a clone that specific organ.  For the sake of this paper, both definitions will be used in order to cover all opinions.

One must understand that cloning does not produce an exact copy of the person being cloned.  What cloning does, is that it copies the DNA/genes of the person and creates a duplicate genetically.  The person will not be a Xerox copy.  He or she will grow up in a different environment than the clone, with different experiences and different opportunities.  Genetics does not wholly define a person and the personality.
  
How It All Started
In February 1997, when embryologist Ian Wilmut and his colleagues at Roslin Institute in Scotland were able to clone a lamb, named Dolly, the world was introduced to a new possibility and will never be the same again (Nash).  Before this, cloning was thought to be impossible, but now there is living proof that the technology and knowledge to clone animals exist.  Questions began to arise within governments and scientific organizations and they began to respond.  Are humans next?  Is it possible to use this procedure to clone humans also?   Would anyone actually try?  What can we learn if we clone humans?  How will this affect the world?  These are only a few of the questions that have surfaced and need answered.  A whole new concept in ethics was created when the birth of Dolly was announced.

There are a great number of possible medical benefits and disadvantages to cloning and its technology. They include the following:
  
Potential Medical Benefits

•   The possibility that through cloning technology we will learn to renew activity of damaged cells by growing new cells and replacing them.
•   The capability to create humans with identical genetic makeup to act as organ donors for each other, i.e., kidney and bone marrow transplants.
•   The benefit of studying cell differentiation at the same time that cloning is studied and developed.
•   Sterile couples will be able to have offspring will have either the mother’s or father’s genetic pattern.
  
Potential Harms and Disadvantages

•   The possibility of compromising individualities.
•   Loss of genetic variation.
•   A “black market” of fetuses may arise from desirable donors that will want to be able to clone themselves, i.e., movie stars, athletes, and others.
•   Technology is not well developed.  It has a low fertility rate.  In cloning Dolly, 277 eggs were used, 30 started to divide, nine induced pregnancy, and only one survived to term (Nash).
•   Clones may be treated as second-class citizens.
•   Unknown psychosocial harms with impacts on the family and society.
  
The Governments Make a Move

The governments went to work shortly after the cloning of Dolly.  They wanted to take control and make laws before anything drastic could ever happen.  Several ethics committees were asked to decide whether scientists should be allowed to try to clone humans.  Many of the committees found the data displayed above.  In the United States, the National Bioethics Advisory Commission recommended a five-year moratorium on cloning a child through somatic cell nuclear transfer (Council on Ethical and Judicial Affairs 1).  In the state of Michigan, Governor Engler signed a law last year making human cloning illegal with harsh penalties if it is attempted (“Governor Engler...”).  In the United Kingdom, the Human Fertilisation and Embryology Authority (HFEA) and the Human Genetics Advisory Commission (HGEC) have approved human cloning for therapeutic purposes, but not to clone children (“HFEA supports Human Cloning in U.K.”).  Many organizations have come out and stated their opinions also.  Amongst all this ethical defining, many people are being ignored by the governments.  People are speaking out about what they want done.
  
Let Us Clone
After a couple has had their first child, to their disappointment they become infertile and cannot have more children.  Cloning would enable such a couple to have a second child, perhaps a younger twin to the child they already have.  This example has a very good argument.  Many couples have difficulties  having children, and sometimes it is impossible for couples to have children because they are infertile.  Cloning would allow these couples to have children.  Also, occasionally a woman is born without a uterus or has other complications and cannot produce eggs, then with the help of a surrogate mother, she can have a child of her own using her own DNA or her husband’s.

This and the example at the beginning are both arguments that some have made in promoting cloning.  It is hard to tell someone that they cannot use cloning to have children when no other possible ways to produce offspring are available.  This is one reason why it is difficult to decide if cloning is ethical or not.  The following are some of the reasons why cloning should be allowed.

As just discussed, cloning can be used to help benefit those that are sterile and cannot have children through the normal, natural way.  It is the desire of most couples to have children and when it is impossible to bare children of your own, some are willing to do anything to have a child.  Cloning will allow them to have a child or many children that have the genetic pattern of one of the parents.

Through cloning, research can progress.  It is hard to say what we can learn from cloning if cloning is not allowed.  We possibly can learn more about cell differentiation.  We can learn enough to produce human organs without having to produce human beings.  We may develop technology to allow easier genetic testing and fixing problems such as spinal cord injuries, cancer, Tay-Sachs disease, and many more.

Cloning organs for organ transplants is one of the major practical reasons that cloning should be allowed.  There is always a high demand for organs.  Some argue for the cloning of humans to create spare body parts.  Others talk of just wanting to clone an organ to replace a defective organ.

Rejuvenation is also a key argument for advocates of cloning.  Human cloning may one day reverse heart attacks.  Some scientists believe that by injecting cloned healthy heart cells into damaged heart tissue will lead to healing of the heart (Human Cloning Foundation).  By combining the technology for cloning and the technology for growing human stem cells, conditions like Alzheimer=s disease, Parkinson=s disease, and degenerative joint disease may be curable.  The possibilities are endless and may be left undiscovered if human cloning is banned.
  
Thou Shalt Not Clone
One of the main goals of the government is to protect human life.  Some people want the government to regulate cloning and not allow it.  Michigan=s government believes this and became the first government to place a ban on cloning.  As mentioned before, the governor signed laws that prohibit engaging or attempting to engage in human cloning.  A Michigan state senator, Mr.  Bennett said, “This legislation boils down to one thing: Prohibiting the creation of human life for scientific research.  Human cloning is wrong; it will be five years from now; and wrong 100 years from now!” (“Governor Engler...”)  Producing clones for research or to use their parts is unethical.  It would be against the code of ethics of a doctor to harm a clone (i.e., use it for an organ transplant).  The clone would be a human being and deserve all the rights and privileges that a non-cloned human has.  A clone should not be a second-class citizen.  It is speculated that they would be considered as such.

The American Medical Association holds four points of reason why cloning should not take place.  They are: 1) there are unknown physical harms introduced by cloning, 2) unknown psychosocial harms introduced by cloning, including violations of autonomy and privacy, 3) impacts on familial and societal relations, and 4) potential effects on the human gene pool (Council on Ethical and Judicial Affairs 4-6).  We just simply do not know the harms that will come from cloning.

Cloning would lead to the loss of individuality because one=s genetic predispositions and conditions would be known.  If raised by a clone-parent or as a sibling to the cloned, one may have great expectations to live up to.  However, the human clones could differ greatly in personality and even grow up with different conditions than the cloned.  Even monozygotic twins differ.  This could be a great stress to the clone and possibly even the loss of ability to chose for itself (Council on Ethical and Judicial Affairs 5).

The long term genetic effects of cloning may cause more problems than can be imagined.  The question of what can go wrong in cloning needs to be discussed.   In an evolutionary standpoint, cloning is not good.  Evolution relies on a continual mixing and matching of genes to keep the gene pool alive (McCormack).  With cloning, the natural process of selection of genes would be bypassed and evolution would be impaired.   The Council of Ethical and Judicial Affairs for the AMA stated the following concerning possible problems with mutations and clones:
Since the somatic cell from which clones originate likely will have acquired mutations, serial cloning would compound the accumulation that occurs in somatic cells.  Although these mutations might not be apparent at the time of cloning, genetics problems could become exacerbated in future generations. (Council on Ethical and Judicial Affairs 6)

We can see that cloning can possibly change the gene pool from how we now know it.  Most likely, it would not be a good change.

Technology as we presently know it will not effectively support the cloning of humans.  As mentioned before, the success rate was quite low when cloning Dolly.  Only one of the 277 tries succeeded, see chart 1.  The same problems of the difficulty of having the fertilized egg implant parallels with that in in vitro fertilization.  Technology has not yet been able to provide an answer to this problem.

The fear that clones will be treated as second-class citizens is also present.   If a clone is created to act as bone marrow or kidney donor, the question arises if they would be treated like the first child?  Would the parents even love this child the same? If not, this would lead to negative self-esteem and/or other physiological problems.  

There is also the fear that some would want to clone people to create large armies of the same soldier or even produce large amounts of workers.  This would also lead to the creation of a second and lower class for clones.

From a Latter-day Saint point of view, the Proclamation on the Family clearly does not agree with cloning.  The Proclamation states: “We . . . declare that God has commanded that the sacred powers of procreation are to be employed only between man and woman, lawfully wedded as husband and wife.  We declare the means by which mortal life is created to be divinely appointed.  We affirm the sanctity of life and of its importance in God’s plan.”  (Italics added)  In other words, the power to create humans is only to be used in a marriage between husband and wife.  Cloning only involves one parent, therefore it is not following God’s plan in which a man’s sperm and a woman’s egg are needed to create life.
  
My Personal Recommendation
As a student studying biology, I have tried to approach both sides and approach them with an unbiased opinion.  I personally think that the world of genetics is fascinating, but after learning of what is now possible through technology, I changed my mind about pursuing a career in the field.  I see cloning as a wonderful advancement in technology and knowledge.  I do not think it should be used to reproduce humans though.  I do not believe that we should try to develop other ways beside the natural way to bring life into this world.  I strongly believe that God created us and that we are subjected to His laws and must obey.  The laws of God that have the worst punishment deal with bringing life into the world and taking life out of the world.  I believe that cloning people would fall under these laws also.  

Cloning tissues and organs falls under a different category that cloning human beings.  I think it would be advantageous to science and medicine to clone tissues and organs.  However, the research in this involves fetal tissue which is a completely different ethical discussion.  I do not know enough about the procedure be against it.  So, with my present understanding I would allow cloning for tissues and organs.
  
Conclusion
Cloning can revolutionize the world and the way we live or it may be so minimal that it would not affect us at all if it is allowed.  The first human to be cloned was reported in Korea by Dr. Kim Seung Bo and Dr. Lee Bo-Yeon.  The clone was born and then killed just days into life (Alton).  Before we knew it, the first clone was created and then destroyed.  Is this the world you want to live in?  Each person individually must decide for himself or herself if they believe that cloning should be allowed or if the governments should intervene with it.

Ó 7 Apr 2000, Joseph Farnsworth

 

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