CLONE

克隆人

克隆人是一个创造的基因完全相同的副本，以前存在的一个现有的或人类。这个名词一般用来指人工克隆人;形式的克隆人，在同卵双胞胎是很常见的繁殖，他们的克隆过程中发生的自然过程。通常有两种类型的讨论人类克隆：治疗性克隆和生殖性克隆。包括克隆治疗性克隆在医学上的成熟细胞，是一个活跃的研究领域。生殖性克隆将涉及制造克隆人类。更换一个克隆的克隆称为第三类是一个理论上的可能性，并且将是一个治疗性和生殖性克隆的组合。更换克隆将产生广泛的更换损坏的，失败，或者未通过或部分身体克隆其次是全脑移植。

克隆人的各种形式是有争议的。[25]克隆领域已经有许多人要求对所有进步的挂起。最科学，政府和宗教组织反对生殖性克隆。在美国科学进步协会的（美国科学促进会）和其他科学组织已得到解决的公开声明表明，人的生殖性克隆加以禁止，直到安全问题。[26]严重的伦理问题提出了克隆器官将来收获的可能性。[ 来源请求 ]有些人认为机体的想法日益机关分别从人-这样做，一个新的器官供应可能没有它们建立从人类的道德意义的收获。研究也正在进行有关的思想成长的器官在生理上可以接受的猪或人体内的其他生物，如牛，然后移植给人类，形成一个异种移植。

人类第一次杂交克隆人创建于1998年11月，由美国电池技术。[27]它是细胞创建从一个人的腿，和一种牛的卵子的DNA被删除。它被摧毁后12天。由于在14天的正常胚胎植入，医生罗伯特兰扎，ACT的工程总监的组织，告诉每日邮报说，胚胎不能被看作是14天前的人。同时使一个胚胎，这可能导致在一个完整的人要是让来而言，根据法令：“[ACT的]目的是'治疗性克隆'不'的生殖性克隆'”

在2008年1月，木材和安德鲁法国，Stemagen的首席科学官在加利福尼亚州宣布，他们成功地创建了第一个5成熟胚使用人类DNA的成年皮肤细胞，旨在提供一个可行的胚胎来源的干细胞。博士塞缪尔伍德和他的同事捐赠的皮肤细胞，这些细胞DNA的人类卵子被转移到。目前尚不清楚，如果将胚胎生产的进一步发展已能，但伍德博士指出，如果这是可能的，使用的生殖性克隆技术将两个不道德的和非法的。 5克隆胚胎，创造了Stemagen公司实验室，拉霍亚，被摧毁。[28]

克隆的伦理问题

主要文章：克隆伦理

由于最近的技术进步，动物克隆（和潜在的人类）一直是一个问题。天主教会和许多宗教组织反对一切形式的克隆，[ 来源请求 ]，理由是在生命始于受孕。犹太教的概念并不等同于生活与和，[ 引文需要 ]虽然一些人质疑克隆智慧，东正教拉比们普遍认为没有理由在公司犹太法律和道德反对克隆。[ 来源请求 ]从古典角度出发自由主义，关注也存在着关于个人的身份，并有权保护自己的遗传特征的保护。

格雷戈里股票是克隆研究的科学家和评论家对直言不讳的限制。[29]生物伦理学家格雷戈里便士也攻击人类思想的犯罪企图克隆。[ 来源请求 ]

人类的生产计划的社会影响是著名的人造探讨奥尔德斯赫胥黎小说美丽新世界。

12月28日，2006年，美国食品和药物管理局（FDA）批准的动物食用肉类和其他产品从克隆。[30]克隆动物性产品被说成是克隆动物几乎没有区别从非。此外，公司不会被要求提供标签告知消费者，肉类来自克隆动物。[31]

批评者提出的消费反对美国FDA人类的动物性产品批准克隆，认为FDA的研究是不够的，不适当的限制，以及可疑的科学有效性。[32][33][34]一些消费者倡导团体工作鼓励跟踪方案，使消费者成为克隆食品和动物产品在其更深入了解。[35]

约瑟夫门德尔松，法律总监食物安全中心表示，克隆食品仍然应被明确标出，因为关于它的安全和伦理问题仍然值得怀疑。

卡罗尔塔克福尔曼，董事粮食政策在美国消费者联盟诞生，美国FDA表示，没有考虑一个事实，一些研究结果表明，克隆动物的死亡率增加和畸形率。

克隆和濒危物种灭绝

克隆，或更确切地说，从重建功能的DNA的灭绝物种，几十年来，一直是科学家的梦想一些。这个问题的可能是戏剧性的畅销小说最好的迈克尔克莱顿和高预算好莱坞惊悚片侏罗纪公园。在现实生活中，一个最克隆的预期目标为曾经是猛犸象，但试图从DNA的提取猛犸被冻结在未获成功，但一个共同的日俄小组目前正在朝着这个目标而努力。[36]

2001年，名为贝西牛生下第一个克隆亚洲野牛，濒危物种，但几天后死亡的两小腿。 2003年，一雄牛克隆成功，随后三个非洲野猫从冷冻胚胎解冻。这些成就为希望（使用其他物种的代母）类似的技术可能被用于克隆已经灭绝的物种。预计这种可能性，bucardo（组织样本上比利牛斯艾贝克斯）被冻结在液氮 2000年去世后，立即研究。研究人员还考虑克隆如大熊猫，豹猫，猎豹和濒危物种。在“ 冷藏动物园“在圣迭戈动物园濒危物种现在商店冷冻组织从世界上最稀有，最。[37][38]

2002年，遗传学家在澳大利亚博物馆宣布，他们已经复制了DNA的袋狼（塔斯马尼亚虎），约65岁以前灭绝，利用聚合酶链反应。[39]然而2005年02月15日宣布，该博物馆是停止测试项目后显示标本的DNA已太严重退化的（乙醇）防腐剂。 2005年，5月15日宣布，该项目将袋狼复活中，研究人员与参与的新新南威尔士和维多利亚州。

2009年1月，第一次，一种已灭绝的动物，上面提到的比利牛斯北山羊进行克隆，在科技研究中心，食品和阿拉贡，利用保存的DNA样本的皮肤和国内从2001年山羊卵细胞。（在山羊出生后不久死亡，由于其肺部生理上的缺陷英寸）[40]

试图克隆已经灭绝的物种之一，在持续的障碍是DNA需要接近完美。从单一的标本克隆能不能创造一个可行的有性繁殖动物繁殖种群。此外，即使男性和女性分别被克隆，这个问题将照常开放是否会在所有的可行的父母，可以教给他们或他们的自然行为的情况下。

克隆濒危物种是高度意识形态化的问题。许多保护生物学家和环境保护主义者强烈反对克隆濒危物种-主要是因为他们认为这可能阻止捐款，以帮助保护自然栖息地和野生动物种群。在“ 规则的拇指“的动物保护是，如果它仍然是可行的和可行的保护野生种群的栖息地，圈养繁殖不应该孤立进行研究。

在2006年的审查，大卫Ehrenfeld的结论是克隆动物的保护是一个实验技术，在其2006年国家中，不能指望单纯的工作机会，除非完全没有通过成本效益分析。[41]此外，他说，它很可能和工作项目，以建立和虹吸资金不能解决任何问题等基本灭绝动物（栖息地的破坏，狩猎或其他过度开发，以及一个贫困的基因池）。虽然克隆技术是行之有效的，并在植物保护上经常使用，必须小心，以确保遗传多样性。他总结说：

克隆脊椎动物构成对环境的风险很小，但它可以保护稀缺资源消耗，以及在维护物种成功的机会似乎很差。迄今为止，转基因的克隆水土保持效益和脊椎动物仍然完全理论性的，但是，许多风险是已知的和记录。保护生物学家应该把他们的研究和精力保护文物的方法建立的，其中没有规定转基因或脊椎动物的克隆。[41]

Human cloning

Main article: Human cloning

Human cloning is the creation of a genetically identical copy of an existing or previously existing human. The term is generally used to refer to artificial human cloning; human clones in the form of identical twins are commonplace, with their cloning occurring during the natural process of reproduction. There are two commonly discussed types of human cloning: therapeutic cloning and reproductive cloning. Therapeutic cloning involves cloning adult cells for use in medicine and is an active area of research. Reproductive cloning would involve making cloned humans. A third type of cloning called replacement cloning is a theoretical possibility, and would be a combination of therapeutic and reproductive cloning. Replacement cloning would entail the replacement of an extensively damaged, failed, or failing body through cloning followed by whole or partial brain transplant.

The various forms of human cloning are controversial.[25] There have been numerous demands for all progress in the human cloning field to be halted. Most scientific, governmental and religious organizations oppose reproductive cloning. The American Association for the Advancement of

Science (AAAS) and other scientific organizations have made public statements suggesting that human reproductive cloning be banned until safety issues are resolved.[26]Serious ethical concerns have been raised by the future possibility of harvesting organs from clones.[citation needed]Some people have considered the idea of growing organs separately from a human organism - in doing this, a new organ supply could be established without the moral implications of harvesting them from humans. Research is also being done on the idea of growing organs that are biologically acceptable to the human body inside of other organisms, such as pigs or cows, then transplanting them to humans, a form of xenotransplantation.

The first human hybrid human clone was created in November 1998, by American Cell Technologies.[27] It was created from a man's leg cell, and a cow's egg whose DNA was removed. It was destroyed after 12 days. Since a normal embryo implants at 14 days, Dr Robert Lanza, ACT's director of tissue engineering, told the Daily Mail newspaper that the embryo could not be seen as a person before 14 days. While making an embryo, which may have resulted in a complete human had it been allowed to come to term, according to ACT: "[ACT's] aim was 'therapeutic cloning' not

'reproductive cloning'"

On January, 2008, Wood and Andrew French, Stemagen's chief scientific officer in California, announced that they successfully created the first

5 mature human embryos using DNA from adult skin cells, aiming to provide

a source of viable embryonic stem cells. Dr. Samuel Wood and a colleague donated skin cells, and DNA from those cells was transferred to human eggs. It is not clear if the embryos produced would have been capable of further development, but Dr. Wood stated that if that were possible, using the technology for reproductive cloning would be both unethical and illegal. The 5 cloned embryos, created in Stemagen Corporation lab, in La Jolla, were destroyed.[28]

Ethical issues of cloning

Main article: Ethics of cloning

Because of recent technological advancements, the cloning of animals (and potentially humans) has been an issue. The Catholic Church and many religious organizations oppose all forms of cloning,[citation needed] on the grounds that life begins at conception. Judaism does not equate life with conception and,[citation needed] though some question the wisdom of cloning, Orthodox rabbis generally find no firm reason in Jewish law and ethics

to object to cloning.[citation needed]From the standpoint of classical liberalism, concerns also exist regarding the protection of the identity of the individual and the right to protect one's genetic identity.

Gregory Stock is a scientist and outspoken critic against restrictions on cloning research.[29] Bioethicist Gregory Pence also attacks the idea of criminalizing attempts to clone humans.[citation needed]

The social implications of an artificial human production scheme were famously explored in Aldous Huxley's novel Brave New World.

On December 28, 2006, the U.S. Food and Drug Administration(FDA) approved the consumption of meat and other products from cloned animals.[30] Cloned-animal products were said to be virtually indistinguishable from the non-cloned animals. Furthermore, companies would not be required to provide labels informing the consumer that the meat comes from a cloned animal.[31]

Critics have raised objections to the FDA's approval of cloned-animal products for human consumption, arguing that the FDA's research was inadequate, inappropriately limited, and of questionable scientific validity.[32][33][34] Several consumer-advocate groups are working to encourage a tracking program that would allow consumers to become more aware of cloned-animal products within their food.[35]

Joseph Mendelson, legal director of the Center for Food Safety, said that cloned food still should be labeled since safety and ethical issues about it remain questionable.

Carol Tucker Foreman, director of food policy at the Consumer Federation of America, stated that FDA does not consider the fact that the results of some studies revealed that cloned animals have increased rates of mortality and deformity at birth.

Cloning extinct and endangered species

Cloning, or more precisely, the reconstruction of functional DNA from extinct species has, for decades, been a dream of some scientists. The possible implications of this were dramatized in the best-selling novel by Michael Crichton and high budget Hollywood thriller Jurassic Park. In real life, one of the most anticipated targets for cloning was once the Woolly Mammoth, but attempts to extract DNA from frozen mammoths have been unsuccessful, though a joint Russo-Japanese team is currently working toward this goal.[36]

In 2001, a cow named Bessie gave birth to a cloned Asian gaur, an endangered species, but the calf died after two days. In 2003, a banteng was successfully cloned, followed by three African wildcats from a thawed frozen embryo. These successes provided hope that similar techniques

(using surrogate mothers of another species) might be used to clone extinct species. Anticipating this possibility, tissue samples from the last bucardo(Pyrenean Ibex) were frozen in liquid nitrogen immediately after it died in 2000. Researchers are also considering cloning endangered species such as the giant panda, ocelot, and cheetah. The "Frozen Zoo" at the San Diego Zoo now stores frozen tissue from the world's rarest and most endangered species.[37][38]

In 2002, geneticists at the Australian Museum announced that they had replicated DNA of the Thylacine(Tasmanian Tiger), extinct about 65 years previous, using polymerase chain reaction.[39] However, on February 15, 2005 the museum announced that it was stopping the project after tests showed the specimens' DNA had been too badly degraded by the (ethanol) preservative. On 15 May 2005 it was announced that the Thylacine project would be revived, with new participation from researchers in New South Wales and Victoria.

In January 2009, for the first time, an extinct animal, the Pyrenean ibex mentioned above was cloned, at the Centre of Food Technology and Research of Aragon, using the preserved DNA of the skin samples from 2001 and domestic goat egg-cells. (The ibex died shortly after birth due to physical defects in its lungs.) [40]One of the continuing obstacles in the attempt to clone extinct species is the need for nearly perfect DNA. Cloning from a single specimen could not create a viable breeding population in sexually reproducing animals. Furthermore, even if males and females were to be cloned, the question would remain open whether they would be viable at all in the absence of parents that could teach or show them their natural behavior.

Cloning endangered species is a highly ideological issue. Many conservation biologists and environmentalists vehemently oppose cloning endangered species — mainly because they think it may deter donations to help preserve natural habitat and wild animal populations. The "rule-of-thumb" in animal conservation is that, if it is still feasible to conserve habitat and viable wild populations, breeding in captivity should not be undertaken in isolation.