Synthetic Biology: Redesigning Life

合成生物学：生命再设计

 

The promise and perils of synthetic biology

合成生物学的希望与风险

 

For the past four billion years or so the only way for life on Earth to produce a sequence of DNA – a gene – was by copying a sequence it already had to hand. Sometimes the gene would be damaged or scrambled, the copying imperfect or undertaken repeatedly. From that raw material arose the glories of natural selection. But beneath it all, gene begat gene.

 

在过去大约40亿年的时间里，地球生命生成基因这种DNA序列的唯一方法就是复制自身已有的遗传DNA序列。有时基因会被破坏或扰乱，复制也会出现缺陷或重复。正是基因这种原材料成就了物竞天择的伟业。但归根结底，基因源自基因。

 

That is no longer true. Now genes can be written from scratch and edited repeatedly, like text in a word processor. The ability to engineer living things which this provides represents a fundamental change in the way humans interact with the planet’s life. It permits the manufacture of all manner of things which used to be hard, even impossible, to make: pharmaceuticals, fuels, fabrics, foods and fragrances can all be built molecule by molecule. What cells do and what they can become is engineerable, too. Immune cells can be told to follow doctors’ orders; stem cells better coaxed to turn into new tissues; fertilised eggs programmed to grow into creatures quite unlike their parents.

 

而这已发生改变。如今，基因就像文字处理软件中的文本，可以被从无到有地编写出来并反复编辑。这样就能改变生物的基因结构，并从根本上改变人类与地球上其他生命的互动方式。过去各种难以甚至不可能制造出来的东西都能被制造，药品、燃料、织物、食品和香水等现在都可以一个分子一个分子地构造出来。还可以通过改变细胞的基因结构来决定细胞的功能和生长结果。可以让免疫细胞听从医生的指令；可以更好地引导干细胞生成新组织；可以编辑受精卵，使之成长为与亲本大不相同的生物。

 

The earliest stages of such “synthetic biology” are already changing many industrial processes, transforming medicine and beginning to reach into the consumer world. Progress may be slow, but with the help of new tools and a big dollop of machine learning, biological manufacturing could eventually yield truly cornucopian technologies. Buildings may be grown from synthetic wood or coral. Mammoths produced from engineered elephant cells may yet stride across Siberia.

 

这种“合成生物学”的初级阶段已经在改变很多工业生产过程，变革医学，并开始影响消费领域。进步可能缓慢，但在各种新工具和大量机器学习的帮助下，生物制造最终可能会带来变幻无穷的技术。合成木材或珊瑚也许可被用来建造房屋。或许还可通过编辑大象细胞的基因结构让猛犸象“复活”，阔步穿过西伯利亚。

 

The scale of the potential changes seems hard to imagine. But look back through history, and humanity’s relations with the living world have seen three great transformations: the exploitation of fossil fuels, the globalisation of the world’s ecosystems after the European conquest of the Americas, and the domestication of crops and animals at the dawn of agriculture. All brought prosperity and progress, but with damaging side-effects. Synthetic biology promises similar transformation. To harness the promise and minimise the peril, it pays to learn the lessons of the past.

 

似乎难以想象未来究竟会有怎样翻天覆地的变化。但是回顾历史，人类与生物世界的关系经历了三次重大转变：化石燃料的开采、欧洲人征服美洲后世界生态系统的全球化，以及农业发端时期对农作物和动物的驯化。三次转变都带来了繁荣和进步，同时也带来了破坏性的副作用。合成生物学预期将带来类似的转变。为把握好机遇并将风险降到最低，有必要汲取前车之鉴。

 

The new biology calls all in doubt

新生物学让一切充满变数

 

Start with the most recent of these previous shifts. Fossil fuels have enabled humans to drive remarkable economic expansion in the present using biological productivity from ages past, stored away in coal and oil. But much wilderness has been lost, and carbon atoms which last saw the atmosphere hundreds of millions of years ago have strengthened the planet’s greenhouse effect to a degree that may prove catastrophic. Here, synthetic biology can do well. It is already being used to replace some products made from petrochemicals; in time it could replace some fuels, too. Burger King recently introduced into some of its restaurants a beefless Whopper that gets its meatiness from an engineered plant protein; such innovations could greatly ease a shift to less environmentally taxing diets. They could also be used to do more with less. Plants and their soil microbes could produce their own fertilisers and pesticides, ruminants less greenhouse gas – though to ensure that synthetic biology yields such laudable environmental goals will take public policy as well as the cues of the market.

 

先从三次转变中距今最近的一次说起。化石燃料的使用释放了过去存储在煤和石油中的生物生产力，大大推动了当今人类经济的发展。但大片荒野不复存在，碳原子上一次充斥于大气是在亿万年前，如今它们的存在大大加重了地球的温室效应，甚至可能导致灾难性后果。在这方面，合成生物学可以有所贡献。它已被用来取代一些石油化工产品，假以时日可能还会取代一些燃料。最近，汉堡王在其部分餐厅推出了一款无牛肉皇堡，其中的肉味来自一种转基因植物蛋白。此类创新可以让人类向更环保饮食方式的转变变得轻松许多。同时，创新还有事半功倍的效果。植物及其土壤微生物可以制造出自身所需的肥料和杀虫剂，反刍动物可以减少排放温室气体。当然，要确保合成生物学达成如此值得称道的环境目标，还需要公共政策以及市场的指引。

 

The second example of biological change sweeping the world is the Columbian exchange, in which the 16th century’s newly global network of trade shuffled together the creatures of the New World and the Old. Horses, cattle and cotton were introduced to the Americas; maize, potatoes, chilli and tobacco to Europe, Africa and Asia. The ecosystems in which humans live became globalised as never before, providing more productive agriculture all round, richer diets for many. But there were also disastrous consequences. Measles, smallpox and other pathogens ran through the New World like a forest fire, claiming tens of millions of lives. The Europeans weaponised this catastrophe, conquering lands depleted and disordered by disease.

 

生物变化席卷世界的第二个例子是哥伦布大交换——16世纪新生成的全球贸易网络将新旧大陆的生物糅合到了一起。马、牛和棉花被引入美洲；玉米、土豆、辣椒和烟草被引入欧洲、非洲和亚洲。人类赖以生存的生态系统前所未有地实现了全球化，为各地提供了更高产的农业，为许多人提供了更丰富的食物。但它也带来了灾难性的后果。麻疹、天花和其他一些病原体像森林大火一样在新大陆肆虐，夺走了数千万人的生命。欧洲人将这场灾难当作武器，用以征服因疾病而衰乱的土地。

 

Synthetic biology could create such weapons by design: pathogens designed to weaken, to incapacitate or to kill, and perhaps also to limit themselves to particular types of target. There is real cause for concern here – but not for immediate alarm. For such weaponisation would, like the rest of cutting-edge synthetic biology, take highly skilled teams with significant resources. And armies already have lots of ways to flatten cities and kill people in large numbers. When it comes to mass destruction, a disease is a poor substitute for a nuke. What’s more, today’s synthetic-biology community lives up to ideals of openness and public service better than many older fields. Maintained and nurtured, that culture should serve as a powerful immune system against rogue elements.

 

合成生物学可能会被利用来蓄意制造这样的武器：能使人衰弱的、致残或致命的病原体，或许还能被限定于攻击特定目标。这确实值得担忧，但眼下还不必恐慌。因为研制这样的武器就像其他前沿合成生物技术那样，需要高技能团队和大量资源。再者，军队已经有很多方式来夷平城市和实施大规模杀戮。疾病在大规模杀伤方面很难匹敌核武器。更重要的是，相比很多旧领域，如今的合成生物学界更符合开放和公共服务的理想原则。若能加以维系和培育，这种文化应该能成为抵御破坏分子的强大免疫系统。

 

The earliest biological transformation – domestication – produced what was hitherto the biggest change in how humans lived their lives. Haphazardly, then purposefully, humans bred cereals to be more bountiful, livestock to be more docile, dogs more obedient and cats more companionable (the last a partial success, at best). This allowed new densities of settlement and new forms of social organisation: the market, the city, the state. Humans domesticated themselves as well as their crops and animals, creating space for the drudgery of subsistence agriculture and oppressive political hierarchies.

 

最早的生物大转变，即驯化，带来了迄今为止人类生活方式的最大变化。从无心到有意，人类将谷物培育得更丰产，让牲畜更温顺，狗更听话，猫更友善（这最后一项充其量只算取得了部分成功）。这促成了更高的聚居密度和新的社会组织形式：市场、城市和国家。人类不仅驯化了农作物和动物，也驯化了自己，让自给型农业的苦役和压迫性的政治等级制度成为可能。

 

Synthetic biology will have a similar cascading effect, transforming humans’ relationships with each other and, potentially, their own biological nature. The ability to reprogram the embryo is, rightly, the site of most of today’s ethical concerns. In future, they may extend further; what should one make of people with the upper-body strength of gorillas, or minds impervious to sorrow? How humans may choose to change themselves biologically is hard to say; that some choices will be controversial is not.

 

合成生物学将产生类似的级联效应，改变人类彼此之间的关系，还有可能改变人类自身的生物学特性。对胚胎重新编辑的能力是如今大多数伦理担忧之所在，对此确实也有担忧的理由。未来，这些担忧可能进一步蔓延：我们该如何看待那些拥有像大猩猩般上肢力量的人，或者那些不知悲伤为何物的人？很难说人类会以何种方式改变自身的生物学特性，但毫无疑问有些选择会引发争议。

        

Which leads to the main way in which this transformation differs from the three that came before. Their significance was discovered only in retrospect. This time, there will be foresight. It will not be perfect: there will certainly be unanticipated effects. But synthetic biology will be driven by the pursuit of goals, both anticipated and desired. It will challenge the human capacity for wisdom and foresight. It might defeat it. But carefully nurtured, it might also help expand it.

                                              

这就引出了此次转变与上述三次转变的主要不同。前三次转变的意义都只是事后的发现。而这一次，我们可以事先预见。这次转变不会完美无缺——肯定会有出人意料的影响。但对预期和期望目标的追求将驱动合成生物学的发展。合成生物学将挑战人类的智慧和远见。或许它会超出人类的能力。但如果精心发展它，却也可能提升人类的这些能力。

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