2021年经济学人 昆虫阉割术,从根上消灭害虫(1)（在线收听）

Pest control

害虫防治

Cas-9-trated

CAS9阉割术

Genetic engineering may help control disease-carrying mosquitoes

基因工程有助于控制携带疾病的蚊子

Every year, hundreds of millions of people catch mosquito-borne diseases like malaria and dengue fever. Hundreds of thousands die. Drug treatments are imperfect. And, despite decades of effort, vaccines have, for many of these diseases, proved tricky to develop.

每年都有数以亿计的人感染疟疾和登革热等蚊媒疾病，成千上万的人因此而死亡。药物治疗并不完美，而且，尽管经过了几十年的努力，但许多此类疾病的疫苗还是难以研制。

Better, then, to stop those infections happening in the first place, by exterminating—or at least suppressing—the mosquitoes that carry the diseases. In a paper just published in the Proceedings of the National Academy of Sciences, a team of researchers led by Craig Montell, of the University of California, Santa Barbara, describe how CRISPR-CAS9, a new and powerful genetic-engineering process, could help to do just that.

那么，最好从一开始就通过消灭——或者至少抑制——携带疾病的蚊子来阻止这些感染的发生。在刚刚发表在《美国国家科学院院刊》上的一篇论文中，由加州大学圣巴巴拉分校的克雷格·蒙特尔领导的一组研究人员，描述了CRISPR-CAS9(一种新的强大的基因工程过程)是如何帮助实现这一目标的。

Dr Montell and his colleagues used CRISPR to boost an existing control method called the sterile insect technique (SIT). This involves releasing lots of sterilised males into the wild. Females that mate with these males produce no offspring. Repeated releases can reduce populations dramatically. SIT has been used in North America to eliminate screwworm flies, an agricultural pest, and to suppress several species of crop-munching fruit flies.

蒙特尔博士和他的同事利用CRISPR技术来增强一种现有的控制方法——昆虫不育技术(SIT)。这项技术需要将很多绝育的雄性放生到野外，与这些雄性交配的雌性不会产下后代，反复进行放生则会大大减少其种群数量。SIT已在北美被用于消灭螺旋蝇(一种农业害虫)并抑制几种吃庄稼的果蝇。

It has been tried on mosquitoes, too, but with less success. One reason seems to be side-effects of the procedure. To sterilise them, males are zapped with radiation or exposed to toxic chemicals. This works, but it damages them in other ways, too. The result can be sickly individuals that struggle to compete in the mating game with their wild counterparts.

这项技术也曾在蚊子身上做过试验，但效果不太好。其中一个原因似乎是过程的副作用。为了使它们绝育，雄性会被辐射或者暴露在有毒化学物质当中。效果是有的，但也会在其它方面有所损害。结果可能就是，病恹恹的个体难以与野生的同类在交配竞争中胜出。

Dr Montell and his colleagues hoped that CRISPR might offer an alternative. Their first step was to look for genes which, when disabled, would render male mosquitoes infertile. They began their hunt in fruit flies, a stalwart of genetic research. They focused on a gene that, when removed, made male fruit flies sterile—and which was present in a similar form in their target mosquito species, Aedes aegypti, which is the vector of, among other illnesses, yellow fever, dengue and Zika virus. Disabling the equivalent gene in male Aedeslikewise left them infertile.

蒙特尔博士和他的同事希望CRISPR能够提供另一种选择。他们的第一步是寻找那些失去功能后会导致雄性蚊子不育的基因。他们开始在果蝇身上寻找基因研究的中坚力量。他们重点研究了一种基因，该基因在去除后会使雄性果蝇不育，而这种基因在他们的目标蚊子种类埃及伊蚊(黄热病、登革热和寨卡病毒等疾病的传播媒介)中以类似的形式存在。