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编辑婴儿?我们需要了解的还有太多

更新时间:2018/11/29 20:49:21 来源:纽约时报中文网 作者:佚名

Editing Babies? We Need to Learn a Lot More First
编辑婴儿?我们需要了解的还有太多

LA JOLLA, Calif. — Sooner or later it was bound to happen. A rogue scientist in China claims to have edited a gene in two human embryos and implanted them in the mother’s womb, resulting in the birth of genetically altered twin girls. We’re no longer in the realm of science fiction. This hacking of their biological operating instructions, which they will pass on to their children and generations to come, is a dangerous breach of medical ethics and responsible research and must be condemned.

加利福尼亚州拉荷亚——这种情况迟早会发生。在中国一名胡作非为的科学家声称,已在两个人类胚胎中编辑了一个基因,将其植入母亲的子宫内,从而导致了一对转基因双胞胎女孩的诞生。这不再是科幻小说的世界了。这对她们的生物运行指令构成了非法入侵,这些指令将被传递给她们的子女和后代,这是对医学伦理和负责任研究的一次危险的违背,必须予以谴责。

This is not to say that medicine won’t someday employ gene-editing technologies in similar ways. But that time has not arrived. There are still too many risks, too many unknowns, about tinkering with our heritable genetic blueprints.

这并不意味着有一天医学中不会以类似的方式使用基因编辑技术。但那个时候还没有到来。关于修补我们可遗传的基因蓝图,仍有太多风险、太多未知因素。

In recent years genome editing has been appropriately heralded as the most important advance of biotechnology of our generation, and most likely the past century. Commonly known as Crispr, this technique and related DNA editing tools enable their users to cut and paste discrete letters of the genome. This capability has markedly advanced science, shedding new light on the complex human genome with its billions of A, C, T and G letters that are the architecture of who we are.

近年来,基因编辑被认为是我们这一代,而且很可能是过去一个世纪以来,生物技术最重要的进步。它通常称为Crispr,这种技术和相关的DNA编辑工具使用户能够剪切和粘贴基因的离散字母。这种能力显著推动了科学的发展,为认识复杂的人类基因研究提供了新的视角,在人类基因之中,数以十亿的A、C、T和G基因字母构成了我们的身体。

Already, many clinical trials using this technology are underway involving patients with rare diseases like hemophilia, thalassemia and sickle cell. The difference between these efforts and what reportedly happened in China is that these genome editing trials involve cells from the patient’s body. The manipulations are not transmissible to the next generation. These trials are in their early stages, and we don’t yet have results to show whether this type of editing is safe or provides effective treatment. But whatever happens, the consequences are confined to the patient, who has consented to the experimental treatment.

目前,许多使用该技术的临床试验正在进行,涉及血友病、地中海贫血和镰状细胞病等罕见疾病患者。这些工作与据报道在中国发生的事情之间的区别在于,这些基因编辑试验使用来自患者身体的细胞,操作不能传递给下一代。这些试验尚处于早期阶段,我们尚未有结果证明此类编辑是否安全,是否能够提供有效治疗。但无论发生什么,其后果都局限于同意实验性治疗的患者。

While there have been reports of human embryo editing experiments in laboratory petri dishes, until now, so far as we know, none of these embryos have been implanted in humans. Here the hazards become markedly amplified because the editing intervenes in so-called germ line cells that are transmitted from one generation to another. Conceivably every cell in the body, some 37 trillion, could be programmed with the edits.

虽然已有关于在实验室培养皿中进行人类胚胎编辑实验的报道,但到目前为止,据我们所知,这些胚胎中没有一个被植入人体。在这个例子里,危害被显著放大,因为编辑干预了从一代传到另一代的所谓的生殖细胞。可以设想身体中的大约37万亿个细胞,都可能被编辑改动了。

In the Chinese study, led by He Jiankui, a physicist, not a medical doctor, on the faculty of Southern University of Science and Technology in Shenzhen, the targeted gene was CCR5, which helps enable H.I.V. to enter cells. While preventing this intrusion might sound like an advance in the fight against AIDS, it is completely unnecessary and may even carry the hazard of increasing the subject’s susceptibility to other types of infection, such as influenza and West Nile fever. Previous genome editing studies have shown it is possible to disable the CCR5 gene in adults without working at the embryo level. So the experiment was not necessary, had no scientific basis and must be considered unethical when balanced against the known and unknown risks.

中国的这项研究由深圳南方科技大学的贺建奎领导,贺建奎是物理学家,而非医生。这项研究的目标基因是CCR5,该基因会帮助HIV进入细胞。虽然防止这种入侵可能听起来像是抗击艾滋病的一种进步,但它完全没有必要,甚至可能增加受试者对其他类型感染的易感性,例如流感和西尼罗河热。先前的基因编辑研究表明,有可能在成年人中禁止CCR5基因,无需在胚胎阶段进行。因此,这个实验没有必要,没有科学依据,在衡量已知和未知风险时肯定会被认为是不道德的。

The predominant risks are the potential impacts of the editing on other letters of the genome, which could induce diseases later in life even if they aren’t present at birth. Although the technology is promising, we don’t have the assurance that Crispr provides laserlike precision in editing. We know, for example, that certain important genes for suppressing cancer are particularly susceptible to unintended editing. The way we assess this risk is to sequence the genome before and after editing, to see whether changes were made in genes other than the target gene. But our ability to discern these changes is still rudimentary, and it is entirely likely that we will miss something. The fact that we may not have seen unintended mutations brought about by editing is by no means proof of their absence. With six billion letters in the genome that could be affected, the risk of unintended, “off target” editing is considerable and requires extensive scrutiny to understand and mitigate. That’s partly why editing the genes of human embryos is prohibited in the United States and banned in many European countries.

其主要风险是编辑对基因中其他字母的潜在影响,即使这些影响在出生时没有显现出来,也可能在以后的生命中诱发疾病。尽管该技术很有前途,但我们并不能确保Crispr在编辑中有着类似激光的精确度。例如,我们知道某些可以抑制癌症的重要基因特别容易受到意外编辑的影响。我们评估这种风险的方法是在编辑之前和之后对基因组进行测序,以确定是否在靶基因以外的基因中进行了改变。但是我们辨别这些变化的能力仍然不成熟,我们很可能会错过一些东西。我们可能没有看到编辑带来的意外突变,这并不能证明这些突变不存在。基因组中有60亿个字母可能受到影响,无意的“脱靶”编辑风险相当大,这种风险需要进行大量仔细审视才能被理解和减轻。编辑人类胚胎基因在美国和许多欧洲国家被禁止,这也是原因之一。

Even beyond the actual editing, this episode appears to have been marked by breaches of scientific conduct. One issue is informed consent. It is unclear whether the parents were told that there were simple ways to protect the embryos from AIDS that might have been transmitted by the H.I.V.-infected father. Given that, why would they consent to this risky procedure?

即使在实际编辑的领域之外,这件事似乎也违反了科学行为的准则。知情同意是一个问题。目前尚不清楚双胞胎的父母是否被告知,还有简单的方法可以保护胚胎不致患上可能由受HIV感染的父亲所传播的艾滋病。既然有简单的方法,他们为什么还要同意这种危险的处理?

Moreover, no report by the researchers has been produced for the biomedical community to review. Through a journalist reporting about this, I had the opportunity to see some of the data, and there’s little question that Dr. He at least attempted to edit the genomes of the embryos. But no sequencing data has been presented or independently assessed. Nor has data been released to show whether the targeted gene was functionally disabled, which would require cell experiments. Science demands such transparency, but all we have is a YouTube video by the researcher, who makes the bold claim that “the gene surgery was safe.”

此外,研究人员没有为生物医学界提供用于审查的报告。通过一篇记者报道,我有机会看到一些数据,毫无疑问,贺建奎至少试图编辑胚胎基因组。但是相关测序数据没有提供或得到独立评估。他也没有公布数据来证明靶基因是否实现了功能禁用,那需要进行细胞实验才行。科学需要这样的透明度,但我们所拥有的只是这位研究者的YouTube视频,他大胆宣称“基因手术是安全的”。

Dr. He’s university has disavowed knowledge or support of the research and said an investigation is underway. It said his “conduct in utilizing CRISPR/Cas9 to edit human embryos has seriously violated academic ethics and codes of conduct.”

贺建奎所在的大学否认了对该研究的知情或支持,并表示正在进行调查。它说“将基因编辑技术用于人体胚胎研究,生物系学术委员会认为其严重违背了学术伦理和学术规范”。

It is difficult to envision a foolproof way to rein in such rogue efforts, notwithstanding the international consensus that we are still nowhere near ready for genome-edited babies. Certainly scientists like Dr. He should be castigated by their institutions and the biomedical community, as he was in this case, and perhaps that will discourage this sort of unethical research. Governments should also condemn these practices and impose significant penalties, like pulling research funding and making these scientists ineligible for more.

虽然国际上一致认为我们仍然远远没有做好准备,去制造基因编辑的婴儿,但很难设想出一种万无一失的方法,可以控制这种胡作非为。当然,像贺建奎这样的科学家应该受到他们所在的机构和生物医学界的抨击,就像他现在所面临的一样,也许这会阻止这种不道德的研究。各国政府还应谴责这些做法,并施加重大惩罚,例如收回研究经费并使这些科学家不再有资格进行更多研究。

At this point, we don’t know whether the intended human genome editing was achieved in the twins and have no idea whether it will prove to be safe if it was accomplished. But we can conclude that this was a misguided, reckless demonstration of using powerful gene-altering tools to create edited human beings. We should not proceed down this road until we know far more about the consequences of what we are doing.

到目前为止,我们不知道这对双胞胎身上是否实现了预期的人类基因编辑,并且不知道如果编辑完成,它是否会被证明是安全的。但我们可以得出结论,这是使用强大的基因改动工具创造被编辑的人类的一次失当、鲁莽的展示。在我们更多了解我们所做事情的后果之前,我们不应该沿着这条道路前进。

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