Cloning/Embryonic Stem Cells
The term cloning is used by scientists to describe many different processes that involve making duplicates of biological material. In most cases, isolated genes or cells are duplicated for scientific study, and no new animal results. The experiment that led to the cloning of Dolly the sheep in 1997 was different: It used a cloning technique called somatic cell nuclear transfer and resulted in an animal that was a genetic twin -- although delayed in time -- of an adult sheep. This technique can also be used to produce an embryo from which cells called embryonic stem (ES) cells could be extracted to use in research into potential therapies for a wide variety of diseases.
Thus, in the past five years, much of the scientific and ethical debate about somatic cell nuclear transfer has focused on its two potential applications: 1) for reproductive purposes, i.e., to produce a child, or 2) for producing a source of ES cells for research.
The technique of transferring a nucleus from a somatic cell into an egg that produced Dolly was an extension of experiments that had been ongoing for over 40 years. In the simplest terms, the technique used to produce Dolly the sheep - somatic cell nuclear transplantation cloning - involves removing the nucleus of an egg and replacing it with the diploid nucleus of a somatic cell. Unlike sexual reproduction, during which a new organism is formed when the genetic material of the egg and sperm fuse, in nuclear transplantation cloning there is a single genetic "parent." This technique also differs from previous cloning techniques because it does not involve an existing embryo. Dolly is different because she is not genetically unique; when born she was genetically identical to an existing six-year-old ewe. Although the birth of Dolly was lauded as a success, in fact, the procedure has not been perfected and it is not yet clear whether Dolly will remain healthy or whether she is already experiencing subtle problems that might lead to serious diseases. Thus, the prospect of applying this technique in humans is troubling for scientific and safety reasons in addition to a variety of ethical reasons related to our ideas about the natural ordering of family and successive generations.
Several important concerns remain about the science and safety of nuclear transfer cloning using adult cells as the source of nuclei. To date, five mammalian species -- sheep, cattle, pigs, goats, and mice -- have been used extensively in reproductive cloning studies. Data from these experiments illustrate the problems involved. Typically, very few cloning attempts are successful. Many cloned animals die in utero, even at late stages or soon after birth, and those that survive frequently exhibit severe birth defects. In addition, female animals carrying cloned fetuses may face serious risks, including death from cloning-related complications.
An additional concern focuses on whether cellular aging will affect the ability of somatic cell nuclei to program normal development. As somatic cells divide they progressively age, and there is normally a defined number of cell divisions that can occur before senescence. Thus, the health effects for the resulting liveborn, having been created with an "aged" nucleus, are unknown. Recently it was reported that Dolly has arthritis, although it is not yet clear whether the five-and-a-half-year-old sheep is suffering from the condition as a result of the cloning process. And, scientists in Tokyo have shown that cloned mice die significantly earlier than those that are naturally conceived, raising an additional concern that the mutations that accumulate in somatic cells might affect nuclear transfer efficiency and lead to cancer and other diseases in offspring. Researchers working with clones of a Holstein cow say genetic programming errors may explain why so many cloned animals die, either as fetuses or newborns.
The announcement of Dolly sparked widespread speculation about a human child being created using somatic cell nuclear transfer. Much of the perceived fear that greeted this announcement centered on the misperception that a child or many children could be produced who would be identical to an already existing person. This fear is based on the idea of "genetic determinism" -- that genes alone determine all aspects of an individual -- and reflects the belief that a person's genes bear a simple relationship to the physical and psychological traits that compose that individual. Although genes play an essential role in the formation of physical and behavioral characteristics, each individual is, in fact, the result of a complex interaction between his or her genes and the environment within which he or she develops. Nonetheless, many of the concerns about cloning have focused on issues related to "playing God," interfering with the natural order of life, and somehow robbing a future individual of the right to a unique identity.
Several groups have concluded that reproductive cloning of human beings creates ethical and scientific risks that society should not tolerate. In 1997, the National Bioethics Advisory Commission recommended that it was morally unacceptable to attempt to create a child using somatic cell nuclear transfer cloning and suggested that a moratorium be imposed until safety of this technique could be assessed. The commission also cautioned against preempting the use of cloning technology for purposes unrelated to producing a liveborn child.
Similarly, in 2001 the National Academy of Sciences issued a report stating that the United States should ban human reproductive cloning aimed at creating a child because experience with reproductive cloning in animals suggests that the process would be dangerous for the woman, the fetus, and the newborn, and would likely fail. The report recommended that the proposed ban on human cloning should be reviewed within five years, but that it should be reconsidered "only if a new scientific review indicates that the procedures are likely to be safe and effective, and if a broad national dialogue on societal, religious and ethical issues suggests that reconsideration is warranted." The panel concluded that the scientific and medical considerations that justify a ban on human reproductive cloning at this time do not apply to nuclear transplantation to produce stem cells. Several other scientific and medical groups also have stated their opposition to the use of cloning for the purpose of producing a child.
The cloning debate was reopened with a new twist late in 1998, when two scientific reports were published regarding the successful isolation of human stem cells. Stem cells are unique and essential cells found in animals that are capable of continually reproducing themselves and renewing tissue throughout an individual organism's life. ES cells are the most versatile of all stem cells because they are less differentiated, or committed, to a particular function than adult stem cells. These cells have offered hope of new cures to debilitating and even fatal illness. Recent studies in mice and other animals have shown that ES cells can reduce symptoms of Parkinson's disease in mouse models, and work in other animal models and disease areas seems promising.
In the 1998 reports, ES cells were derived from in vitro embryos six to seven days old destined to be discarded by couples undergoing infertility treatments, and embryonic germ (EG) cells were obtained from cadaveric fetal tissue following elective abortion. A third report, appearing in the New York Times, claimed that a Massachusetts biotechnology company had fused a human cell with an enucleated cow egg, creating a hybrid clone that failed to progress beyond an early stage of development. This announcement served as a reminder that ES cells also could be derived from embryos created through somatic cell nuclear transfer, or cloning. In fact, several scientists believed that deriving ES cells in this manner is the most promising approach to developing treatments because the condition of in vitro fertilization (IVF) embryos stored over time is questionable and this type of cloning could overcome graft-host responses if resulting therapies were developed from the recipient's own DNA.
For those who believe that the embryo has the moral status of a person from the moment of conception, research or any other activity that would destroy it is wrong. For those who believe the human embryo deserves some measure of respect, but disagree that the respect due should equal that given to a fully formed human, it could be considered immoral not to use embryos that would otherwise be destroyed to develop potential cures for disease affecting millions of people. An additional concern related to public policy is whether federal funds should be used for research that some Americans find unethical.
Since 1996, Congress has prohibited researchers from using federal funds for human embryo research. In 1999, DHHS announced that it intended to fund research on human ES cells derived from embryos remaining after infertility treatments. This decision was based on an interpretation "that human embryonic stem cells are not a human embryo within the statutory definition" because "the cells do not have the capacity to develop into a human being even if transferred to the uterus, thus their destruction in the course of research would not constitute the destruction of an embryo." DHHS did not intend to fund research using stem cells derived from embryos created through cloning, although such efforts would be legal in the private sector.
In July 2001, the House of Representatives voted 265 to 162 to make any human cloning a criminal offense, including cloning to create an embryo for derivation of stem cells rather than to produce a child. In August 2002, President Bush, contending with a DHHS decision made during the Clinton administration, stated in a prime-time television address that federal support would be provided for research using a limited number of stem cell colonies already in existence (derived from leftover IVF embryos). Current bills before Congress would ban all forms of cloning outright, prohibit cloning for reproductive purposes, and impose a moratorium on cloning to derive stem cells for research, or prohibit cloning for reproductive purposes while allowing cloning for therapeutic purposes to go forward. As of late June, the Senate has taken no action. President Bush's Bioethics Council is expected to recommend the prohibition of reproductive cloning and a moratorium on therapeutic cloning later this summer.
Prepared by Kathi E. Hanna, M.S., Ph.D., Science and Health Policy Consultant
Last Reviewed: April 2006
Read the original here:
Cloning/Embryonic Stem Cells - National Human Genome ...
- Growing Organs in the Lab: One Step Closer to Reality - BioSpace - November 21st, 2019
- Major step taken in creating complex organs in the lab - Drug Target Review - November 21st, 2019
- Cell Therapy Aims To Improve Memory and Prevent Seizures Following Traumatic Brain Injury - Technology Networks - November 21st, 2019
- WCM-Q explores law and ethics of stem cells and AI in medicine - The Peninsula Qatar - November 18th, 2019
- Qatar- WCM-Q explores law and ethics of stem cells and AI in medicine - MENAFN.COM - November 18th, 2019
- New cell therapy improves memory and stops seizures after brain injury - Drug Target Review - November 18th, 2019
- Stem Cell Therapy Market by Treatment,Application,End Users and Geography Forecast To 2026 - Markets Gazette 24 - November 11th, 2019
- Global Stem Cell Assay Market 2019 Size, Share, Growth, Trends, Type, Application, Analysis and Forecast by 2026 - Markets Gazette 24 - November 11th, 2019
- Oct4, Considered Vital for Creating iPSCs, Actually Isnt Needed - The Scientist - November 8th, 2019
- A winding romp through advances in cell biology pushes readers to ponder the boundaries of life - Science Magazine - October 31st, 2019
- Cell Banking Outsourcing Market to 2027 - Global Analysis and Forecasts By Product Type (Cord Cell Banking, Adult Stem Cell Banking, Embryonic Stem... - October 31st, 2019
- Cell Isolation Market ||Becton, Dickinson, and Company, Thermo Fisher Scientific, Inc., Merck KGaA - Industry News Info - October 31st, 2019
- Scientists Made Mice Live 12% Longer by Hacking Their Telomeres - Futurism - October 22nd, 2019
- Scientists extend mice lifespan 12% by tweaking telomeres - Big Think - October 22nd, 2019
- Merck KGaA opens Shanghai Innovation Center and invests $ 14 million in the China Seed Fund - asume tech - October 19th, 2019
- Health policy will be the focus of the HLTH - asume tech - October 19th, 2019
- Syros sees strategic shift after the failure of the previously promising cancer drug - asume tech - October 19th, 2019
- What Theranos Whistleblowers Learn About Ethics in Health Startups - asume tech - October 19th, 2019
- Assessments of Treatment Options for Age-related Macular Degeneration - DocWire News - October 15th, 2019
- Stem Cells Market Growth Rate, Production Volume and Future Opportunities From 2019-2024 - Exponent Online - October 15th, 2019
- Catholics more motivated to donate if ethical investing is assured - Crux: Covering all things Catholic - October 10th, 2019
- Greenwood to step down as CEO of BIO after 2020 election - FierceBiotech - October 10th, 2019
- Epigenetic initiation of the TH17 differentiation program is promoted by Cxxc finger protein 1 - Science Advances - October 10th, 2019
- Interview with Tamer Mohamed of Aspect Biosystems on Advancing Tissue Therapeutics - 3DPrint.com - October 10th, 2019
- Yale researchers develop way to help brain organoids thrive - Yale News - October 9th, 2019
- Catholics more motivated to donate if ethical investing is assured - The Catholic Spirit - October 9th, 2019
- Stem Cell Market: By Key Players, Market Competitive Landscape, Trends and Forecasts to 2024 - Joliet Observer - October 9th, 2019
- Stem Cell Therapy Market to Witness a Pronounce Growth During 2020 - Gem Newz - October 9th, 2019
- On creativity, plasticity and repentance - Arutz Sheva - October 5th, 2019
- What's in the cards for this year's Nobel Prizes? - STAT - October 2nd, 2019
- Moving beyond hype: Could one-two treatment restore damaged heart muscle? - University of Wisconsin-Madison - September 28th, 2019
- Conjugated polymers optically regulate the fate of endothelial colony-forming cells - Science Advances - September 28th, 2019
- God of miniscule things - Pune Mirror - September 27th, 2019
- New study shows insight into how cells maintain their identity - Drug Target Review - September 24th, 2019
- Human Embryonic Stem Cells Market: Expansion Strategies Set to Generate Substantial Revenue in the near Future - Rapid News Network - September 24th, 2019
- Global Stem Cells Market 2019 Strategic Assessment by Top Players CCBC, Vcanbio, Boyalife, Beikebiotech - News Coed - September 24th, 2019
- Study Gives Clues to the Origin of Huntington's Disease, and a New Way to Find Drugs - Nature World News - September 24th, 2019
- Global Stem Cells Market 2019 Business Statistics Focus Report Growth by Top Key Players CCBC, Vcanbio, Boyalife, Beikebiotec - The Industry News... - September 24th, 2019
- Orthopedic Biomaterials Product Market Set to Witness YoY Growth by 2018-2026 - NewsStoner - September 24th, 2019
- Global Fetal Bovine Serum Market : Industry Analysis and Forecast (2017-2026) - OnYourDesks - September 24th, 2019
- Stem Cell Therapy Market to Discern Steadfast Expansion During 2020 - Technology Trend - September 24th, 2019
- Embryonic Stem Cell - an overview | ScienceDirect Topics - May 22nd, 2019
- Embryonic Stem Cell Research and Vaccines using Fetal Tissue - May 6th, 2019
- Embryonic Stem Cells - Definitions, Use, and Research - April 28th, 2019
- Will Embryonic Stem Cells Ever Cure Anything? - MIT ... - April 28th, 2019
- Creating Embryonic Stem Cells Without Embryo Destruction - April 23rd, 2019
- What Are Stem Cells? - livescience.com - April 19th, 2019
- Embryonic Stem-Cell Research Reaches Moral, Medical Dead End - April 8th, 2019
- Embryonic Stem Cell: Definition, Uses and Collection ... - April 2nd, 2019
- Advantages of Embryonic Stem Cell Research | Sciencing - March 30th, 2019
- Practical Problems with Embryonic Stem Cells - usccb.org - March 20th, 2019
- Obama Ends Stem Cell Research Ban - CBS News - March 10th, 2019
- Types of Stem Cells A Closer Look at Stem Cells - January 26th, 2019
- Embryonic Stem Cell Research - rtlofneo.com - December 19th, 2018
- The Ethics Of Embryonic Stem Cell Research Viewpoint Essay - December 11th, 2018
- Embryonic Stem Cells and Artificial Stem Cells Are ... - December 5th, 2018
- Embryonic stem cells | Cells | MCAT | Khan Academy - November 25th, 2018
- Crucial Differences Between Non-Embryonic and Embryonic Stem ... - November 23rd, 2018
- 14 Key Pros and Cons of Embryonic Stem Cell Research ... - November 5th, 2018
- Human Embryonic Stem Cells in Development, Volume 129 ... - September 29th, 2018
- Reprogrammed stem cells identical to embryonic stem cells - September 29th, 2018
- Embryonic Stem Cell Protocols by Kursad Turksen | Waterstones - September 29th, 2018
- What Are Stem Cells? Research, Transplant, Therapy, Definition - July 17th, 2018
- Embryonic Stem Cell Research Pros and Cons | HRFnd - June 19th, 2018
- Stem Cell Research: Is It in Danger? - September 29th, 2017
- Truth About Embryonic Stem Cells | Stem Cell Orthopedic ... - September 29th, 2017
- Embryonic Stem Cell Research Still Hasn't Cured a Single ... - September 25th, 2017
- Doubts raised about CRISPR gene-editing study in human embryos - Nature.com - September 2nd, 2017
- Study shows human stem cells restore mobility in Parkinson's monkeys - Borneo Bulletin Online - September 2nd, 2017
- Sofa Vergara's ex might finally be out of luck in his battle for custody ... - Slate Magazine (blog) - September 1st, 2017
- Young cardiac cells rejuvenate heart in animal study - The San Diego Union-Tribune - August 29th, 2017
- embryonic stem cells : NPR - August 25th, 2017
- Mouse model of human immune system inadequate for stem cell studies - Stanford Medical Center Report - August 25th, 2017
- Injections of Vitamin C Could Help Fight Blood Cancer - Wall Street Pit - August 25th, 2017
- Letter: Response to 'Disappointed by Republicans' - The Herald-News - August 20th, 2017
- What are Embryonic Stem Cells? - amaskincare.com - August 19th, 2017
- Woman Will Use Stem Cells From Her Baby's Umbilical Cord To ... - LifeNews.com - August 19th, 2017
- Stem cells mimic sphere where embryos grow - Futurity: Research News - August 19th, 2017
- Vitamin C helps genes to kill off cells that would cause cancer - New Scientist - August 19th, 2017
- A way to stabilize haploidy in animal cells - Phys.Org - August 16th, 2017