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BERKELEY, Calif. — AN advisory committee of the Food and Drug Administration is set to begin two days of meetings tomorrow to consider radical biological procedures that, if successful, would produce genetically modified human beings. This is a dangerous step. These techniques would change every cell in the bodies of children born as a result of their use, and these alterations would be passed down to future generations.加利福尼亚州伯克利——食品与药品管理局(Food and Drug Administration,全称FDA)的一个顾问委员会订于明天开始一个为期两天的会议,对一种全新的生物手段加以考量,这种手段一旦顺利,将产生经过基因改动的人类。这是危险性的一步。这些技术将转变一个新生儿全身上下的每一个细胞,其后代也将承继这些转变。
The F.D.A. calls them mitochondrial manipulation technologies. The procedures involve removing the nuclear material either from the egg or embryo of a woman with inheritable mitochondrial disease and inserting it into a healthy egg or embryo of a donor whose own nuclear material has been discarded. Any offspring would carry genetic material from three people — the nuclear DNA of the mother and father, and the mitochondrial DNA of the donor.FDA称作线粒体操作者技术。涉及的步骤牵涉到将患上遗传性线粒体疾病的女性的卵子或胚胎的核质放入,映射到捐赠者的身体健康卵子或胚胎中,捐赠者本身的核质早已弃置。所有子女都将装载三个人的基因物质,分别是父亲和母亲的核DNA以及捐赠者的线粒体DNA。
Roughly 1,000 to 4,000 children born in the United States each year will develop a mitochondrial disease, most by age 10, with symptoms that can range from mild to devastating. These diseases typically prevent mitochondria from converting food into energy and are the result of genetic abnormalities, although some cases can be caused by exposures to toxins. Disorders caused by mutations in the mitochondrial DNA are passed down from the mother.美国每年有1000到4000名新生儿患上线粒体疾病,大多数在10岁以前发作,症状有的严重,有的十分相当严重。这类疾病一般来说不会制止线粒体将食物转化成为能量,是基因出现异常的结果,不过某些情况下也有可能因认识毒素造成。线粒体DNA变异造成的障碍症会通过母亲传授给下一代。
Developers of these modification techniques say they are a way for women with mitochondrial disease to give birth to healthy children to whom they are related genetically. Some are also promoting their use for age-related infertility. These are worthy goals. But these procedures are deeply problematic in terms of their medical risks and societal implications. Will the child be born healthy, or will the cellular disruptions created by this eggs-as-Lego-pieces approach lead to problems later on? What about subsequent generations? And how far will we go in our efforts to engineer humans?基因改动技术的开发人员称之为,用于这种技术可以让患上线粒体疾病的女性生下身体健康的孩子,同时与孩子还有基因关联。另外一些人特别强调这种技术可用作与年龄涉及的不孕不育。这些都是有价值的目标。
但是这些手段在医疗风险和社会意义方面具有深层次的问题。生下的孩子是不是身体健康,或者,这种拿细胞当乐高积木的方法产生的细胞阻碍否不会造成日后的问题?后代又不会如何?我们在人类转基因上即将回头多近?These sorts of concerns were first voiced decades ago, well before the human genome had even been mapped. Those were the days when our accelerating knowledge about genetics led to over-optimistic hopes for quick fixes to an array of afflictions and grandiose visions of designing genetically enhanced babies to be more intelligent, athletic, musically talented and the like.这些都是几十年前就早已明确提出的忧虑,而那时连对人类基因组的“绘图”都预想开始。在那个年代,遗传学的很快发展令其我们产生了过分悲观的期望,指出它可以老大我们寻找化疗诸多疾病的捷径,并描绘出有经过基因提高的婴儿的宏大设计蓝图,期望通过改良把孩子显得更聪明,在运动和音乐等方面极具天赋。
More recently, many scholars, scientists and policy makers have urged a different approach: We should carefully and thoughtfully apply the tools of human genetic engineering to treat medical conditions in people, but we should not use them to manipulate the genetic traits of future children. Genetic modifications of sperm, eggs and early embryos should be strictly off limits. Otherwise, we risk venturing into human experimentation and high-tech eugenics.而近些年来,许多学者、科学家和政策制定者开始敦促自由选择另一种路线:我们应当小心而周密地去运用人类基因手段化疗疾病,但我们不应当用这些手段去操纵未来孩子的基因性状。精子、卵子和早期胚胎的基因改动应当受到严苛容许,否则我们就有可能陷于人类实验和高科技优生学的危险性境地。Unfortunately, there are now worrisome signs that opposition to inheritable genetic modifications, written into law by dozens of countries, according to our count, may be weakening. British regulators are also considering mitochondrial manipulations, and proponents there, like their counterparts in the United States, want to move quickly to clinical trials.意外的是,目前经常出现了一些令人担忧的迹象,根据我们的统计资料,对遗传性基因改动的违背正在弱化——这种改动在许多国家是被法律禁令的。
英国监管机构也在考虑到线粒体操纵技术,那里的倡导者跟在美国的同道一样,期望尽早进行临床试验。Researchers at Oregon Health and Science University have produced five macaque monkeys using one of these techniques. Four are now adults and all five appear healthy. But we wont know for years how subsequent generations may be affected.俄勒冈身体健康与科学大学(Oregon Health and Science University)的研究人员用于其中一项技术培育了五只猕猴。五只猴子目前显然都是身体健康的,其中四只早已成年。
但我们要再行等几年才能告诉后代不会受到什么影响。And the O.H.S.U. researchers themselves report a difference between their experience with the macaques and their work so far on fertilized human eggs. More than half of the human zygotes — single cells formed by the merging of an egg and sperm — had abnormalities not observed in the fertilized eggs of the monkeys. It looks like human oocytes are more sensitive, the lead researcher, Shoukhrat Mitalipov, a reproductive biologist, told Nature.该大学的研究人员自己也在报告中提及,这次猕猴实验和他们目前为止用接受炼的人类卵子展开的研究是有差异的。多达一半的人类受精卵——卵子和精子融合构成的单个细胞——经常出现了在猴子受精卵中没仔细观察到的出现异常。
“看上去人类的卵细胞更加脆弱,”生殖生物学家、本次研究的首席研究员舒哈拉兹·米塔利波夫(Shoukhrat Mitalipov)对《大自然》(Nature)杂志说道。Some media accounts about these techniques have misleadingly referred to saving lives, as if they were aimed at people who are sick and suffering. Others have failed to note how very few women would be candidates for even considering them. And they could turn to safer and simpler alternatives. An affected woman could adopt or use in vitro fertilization with another womans eggs. Of course, the resulting child would not be genetically related to her, but neither would the child be put at grave risk by an extreme procedure.部分媒体在报导中误导性地称作“救命的”技术,好像它们面向的是不受病痛后遗症的人。还有一些报导没有能具体一点,要去考虑到用于这些技术的女性少之又少。
她们有更加安全性、更加非常简单的方案可选。患病的女性可以自由选择领养,或用于另一名女性的卵子展开体外受精。
当然,这样一来她和孩子将不不存在基因上的关联,但同时也让孩子免遭分担极端手段带给的可怕风险。The F.D.A. advisory panel says that its meeting will consider only scientific aspects of mitochondrial manipulation and that any ethical and social policy issues are outside its scope. But those are precisely the issues that we must address. Simply being able to do something doesnt mean we should do it.FDA顾问专家组称之为,此次会议对线粒体操作者的思维将仅限于科学层面,任何“伦理和社会政策问题”都不出注目范畴内。
然而我们必须面临的才是就是这些问题。不具备做到某件事的能力并不等于我们就应当去做到它。
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