“完美人”离我们有多远

So it begins. Nobody thought it would happen this fast, and now we are preparing to take a leap into the unknown. Not Brexit but Crispr gene-editing, a DNA¹-changing technology that can supposedly cure mice of liver disease and muscular dystrophy, render human cells resistant² to HIV and create fungus-resistant wheat.

就这么开始了。没人想到这件事来得这么快，现在我们正准备跃入未知之中。这里说的不是英国退欧，而是“成簇规律间隔短回文重复序列”(Crispr)基因编辑，一种据信能够治愈小鼠的肝病和肌营养不良，让人类细胞对艾滋病毒(HIV)产生抗性，培育出抗真菌小麦的DNA改造技术。

It has also been touted³ as a means of remaking humanity — and now it is about to progress from Petri dishes into people. An influential⁴ advisory⁵ panel at the US National Institutes of Health has unanimously approved the first clinical trial to use Crispr genome-editing (also known as gene-editing) on humans, to reboot immune cells in cancer patients. Researchers at the University of Pennsylvania will target patients with multiple myeloma, melanoma or sarcoma. The team will remove a class of immune cells called T-cells from patients, edit the genes⁶ of those T-cells so they are better able to “lock on” to tumour⁷ cells, and then restore the altered T-cells back into the bloodstream.

该技术也被吹捧为一种再造人类的手段，现在这种技术即将从培养皿走向人类。美国国家卫生研究院(NIH)一个有影响力的顾问组已一致批准第一项对人类使用Crispr基因组编辑（也称基因编辑）技术，以“重启”癌症病人免疫细胞的临床试验。宾夕法尼亚大学(University of Pennsylvania)的研究人员将以多发性骨髓瘤、黑色素瘤或肉瘤患者为对象。该团队将从患者体内取出被称为T细胞的一类免疫细胞，对这些T细胞的基因进行编辑，使它们能更好地“锁定”癌细胞，然后将这些修改过的T细胞重新导入患者的血液循环系统。

With luck, the genetic⁸ edits should boost the patient’s immune system. The study, now expected to receive the blessing⁹ of federal regulators, will be funded by a cancer institute founded by Sean Parker of Napster and Facebook fame.

幸运的话，基因编辑应该能促进患者的免疫系统。预计将获得联邦监管机构的批准的这项研究，将由曾经创立Napster、并担任Facebook首任总裁的肖恩•帕克(Sean Parker)创办的一个癌症研究所资助。

The aim of this first in-human trial of Crispr is not to enhance therapeutic¹⁰ outcomes but to prove its safety. Other genetic technologies of great pro-mise cast long shadows. Gene therapy, which involves inserting copies of missing or defective¹¹ genes into a patient, usually using a virus as a carrier, was nearly derailed at the turn of the millennium¹² , when a child with a severe immune disorder¹³ developed leukaemia as a direct result of the treatment.

这个对人体进行的第一项Crispr实验的目的，不是为了改善治疗结果，而是为了证明其安全性。其他曾经大有希望的基因技术投下了长长的阴影。向患者体内注入缺失或者缺陷基因的副本（通常使用病毒作为载体）的基因疗法，在世纪之交的时候几乎遭到毁灭性打击，当时这种疗法直接导致一名患有严重的免疫紊乱症的儿童罹患白血病。

The viruses chosen as carriers in some early trials wrought¹⁴ unforeseen damage. As a result the first European treatment using gene therapy, which has been around since 1990, was licensed¹⁵ only in 2012.

在一些早期的试验中，被选为载体的病毒造成了无法预见的伤害。其结果是，基因疗法虽然从1990年起就存在了，但欧洲第一例使用这种疗法的治疗在2012年才获得许可。

With gene-editing, the unintended consequence¹⁶ that most terrifies genetic researchers is “off-target effects”, in which untargeted genes are inadvertently snipped¹⁷, deleted or altered. The technology uses enzymes¹⁹ to search for particular sequences of DNA — but, just as it is possible for a search facility in word-processing software to pick out a string of letters in an unexpected place, the enzymes might similarly latch²⁰ on to the wrong stretch of DNA.

就基因编辑而言，最让基因研究人员感到惊恐的意外后果是“脱靶效应”，也就是非靶向基因被不慎剪断、移除或者修改。基因编辑技术利用酶来搜寻特定的DNA序列，但就像文字处理软件的搜索功能可能在意想不到的地方挑出一串字符那样，酶也可能以类似的方式附着于错误的DNA片段。

The risk, at least in this trial, is minimised by the gene-editing being done outside the body, allowing researchers to check the T-cells have been appropriately amended²¹ before being put back into the patient. Still, once the cutting enzyme¹⁸ is unleashed²², there is a possibility it could continue operating inside the body to uncertain end.

至少在这次实验中，这种风险被最小化——通过从人体外进行基因编辑，研究者能在检查T细胞已被适当地修改之后，再将其导入患者体内。话虽如此，一旦剪切酶被释放出来，其依然有可能在人体内发挥不确定的作用。

By next year we should have a hint²³ of whether gene-editing really can fix deficient²⁴ DNA in people. And that is when things get serious: why stop at correcting the human genome? Why not beautify it? That thought is preoccupying²⁵ those in the field, who raised concerns at a Washington summit in December, organised by scientists from the UK, China and the US. Among those attending was Yale University’s Daniel Kevles, a historian of the eugenics movement.

到了明年，我们应该就能对基因编辑是否真的能修复人的缺陷DNA有所了解。这就是事情开始变严重的地方：为何要止步于修正人类基因组呢？何不对其进行美化？这种想法让该领域的人士忧心忡忡，在去年12月由英国、中国和美国科学家组织、在华盛顿举行的一次峰会上，他们提出了这种担忧。与会者包括来自耶鲁大学(Yale University)的优生运动历史学家丹尼尔•凯夫利斯(Daniel Kevles)。

The thing about Crispr genome-editing is this: it is fast, cheap and easy to do. Many countries, especially those that see themselves as future torchbearers for technology, such as China, are forging ahead; China holds the first claim to creating a (non-viable) gene-edited embryo²⁶. Regulation is patchy.

Crispr基因组编辑有这样一个特点：这种技术快速、廉价和易行。许多国家，尤其是那些视自身为这些技术未来旗手的国家，比如中国，正在大力推进；中国是第一个声称对（无法存活的）人类胚胎进行过基因编辑的的国家。相关法规还不健全。

No country endorses²⁷ a genome-edited human embryo being implanted and being brought to term. Even so, gene-editing technology makes the prospect²⁸ of a homo perfectus just slightly more probable — and, as a species, we have yet to fully grasp the implications of this brave and perfectly²⁹ edited new world.

目前没有哪个国家批准将经过基因组编辑的人类胚胎植入母体直至足月分娩。即使如此，基因编辑技术略微提高了实现“完美的人”(homo perfectus)的可能性——作为一个物种，我们还没有完全想好这个经过完美编辑的大胆新世界会有什么影响。