纽约时报 令人爱恨交加的转基因作物(4)（在线收听）

Despite that, plant geneticists tend not to be overly concerned about the risks of G.M.O.s, as long as the modifications are made with some care. As a 2016 report by the National Academy of Sciences found, G.M.O.s were generally safe, though it allowed that minor impacts were theoretically possible. Fred Gould, a professor of agriculture who was chairman of the committee that prepared the 600-page report, noted that genetic changes that alter a metabolic pathway — the cellular process that transforms biochemical elements into a particular nutrient or compound — were especially important to study because they could cause cascading effects.

尽管如此，只要修改是谨慎进行的，植物遗传学家往往不会过度担心转基因生物的风险。正如美国国家科学院2016年一份报告所发现的那样，转基因生物总体上是安全的，尽管它允许理论上产生轻微影响的可能性。农业教授、编写这份600页报告的委员会主席弗雷德·古尔德指出，改变代谢途径的基因变化——将生化元素转化为特定营养物质或化合物的细胞过程——对他们的研究非常尤其重要，因为它们可能会引起级联效应。

If we don't find these sorts of distinctions very reassuring, it's in part because our extravagant concern about G.M.O.s reflects something more fundamental: the fact that most of us don't really understand how genes work. As several scientists I spoke with pointed out, a gene is just a narrow set of biological instructions, many of which appear across a wide range of species. That something could be anthocyanin, or it could be a dangerous toxin, but the knob itself isn't the problem, nor is the process by which it was added.

如果我们认为这些区别不太令人放心，部分原因是我们对转基因生物的过度担忧反映了一些更基本的东西：我们大多数人并不真正了解转基因的原理。正如我采访的几位科学家所指出，基因只是一套狭窄的生物学指令，其中许多指令出现在各种各样的物种中。它可能是花青素，也可能是一种危险的毒素，但基因本身不是问题，添加它的过程也不是问题。

In practice, of course, almost everything we grow and eat today has had its DNA altered extensively. For millenniums, farmers, discovering that one version of a plant — usually a random genetic mutant — was hardier, or sweeter, or had smaller seeds, would cross it with another that, say, produced more fruit, in hopes of getting both benefits. But the process was slow. Simply changing the color of a tomato from red to yellow while preserving its other traits could take years of crossbreeding. And tomatoes are one of the easiest cases. Introducing even a minor change to a cherry through crossbreeding, I was told, could take up to 150 years.

当然，在实践中，我们如今种植和食用的几乎所有东西的DNA都发生了广泛变化。几千年来，如果农民发现一种植物的某个版本——通常是随机的基因突变——更耐寒、更甜或种子更小，他们就会将其与另一个生产更多果实的版本进行植物杂交，以期两者兼得。但这一过程很慢。仅仅将番茄的颜色从红色变为黄色，同时保留它的其他特性，可能就需要进行数年的杂交才能实现。番茄是最容易改变的作物之一。我了解到，通过杂交育种使樱桃发生哪怕是很小的变化，也可能需要长达150年的时间。