第1562期:Scientist create gene-edited pigs

By now, most of us will have heard of GMOs. In case you haven't, GMO stands for genetically-modified organism. This basically means that an organism has had a foreign genetic sequence introduced into it. In theory, this gives the organism certain advantages – it may become hardier by developing a resistance to disease, or in the case of GM food, may be bigger and require fewer nutrients to develop.

到目前为止，我们大多数人都会听说过转基因生物。如果你还没有，GMO 代表转基因生物。这基本上意味着一个有机体已经引入了一个外来基因序列。从理论上讲，这给有机体带来了一定的优势——它可能会因为对疾病产生抵抗力而变得更强壮，或者在转基因食品的情况下，它可能更大，需要更少的营养来发育。

GM organisms have been used for a while. Scientists in the UK are trialling a GM wheat which allegedly yields40% more crop in greenhouse conditions. GM hens, which are able to lay eggs from different poultry breeds, have been used by scientists in Edinburgh to conserve rare birds by storing their stem cells in a seed bank. And more recently, scientists in China used information from the genome of a plant to increase the production of a key malaria drug, helping to meet the large global demand.

转基因生物已经使用了一段时间。英国科学家正在试验一种转基因小麦，据称这种小麦在温室条件下的产量增加了 40%。能够从不同家禽品种产卵的转基因母鸡已被爱丁堡的科学家用来通过将干细胞储存在种子库中来保护稀有鸟类。最近，中国的科学家利用植物基因组的信息来增加一种关键疟疾药物的产量，帮助满足全球的巨大需求。

But now scientists at the University of Edinburgh's Roslin Institute have created GE pigs which are allegedly immune to one of the world's costliest livestock diseases. GE stands for gene editing. Unlike GM, gene editing merely alters the DNA of the creature. In this case, a small region of pig DNA was deleted, preventing contraction of the PRRS virus, or Porcine Reproductive and Respiratory Syndrome virus.

但现在爱丁堡大学罗斯林研究所的科学家们已经创造出转基因猪，据称这些猪对世界上最昂贵的牲畜疾病之一具有免疫力。GE代表基因编辑。与转基因不同，基因编辑仅仅改变了生物的 DNA。在这种情况下，猪的一小部分 DNA 被删除，从而防止了 PRRS 病毒或猪繁殖和呼吸综合征病毒的收缩。

The virus causes breathing problems and death, but even after the GE pigs were exposed to it, none have become ill. And the effect is permanent, so the resistance will be passed on through natural breeding. Tests so far showed that the animals are not weakened in any other way by the process, claims Research leader Dr Christine Tait-Burkard. "The main thing that this edit will do is benefit animal welfare because the animals will not get a devastating disease."

这种病毒会导致呼吸困难和死亡，但即使在转基因猪暴露于病毒之后，也没有人生病。而且效果是永久性的，所以抵抗力会通过自然繁殖传递。研究负责人克里斯汀·泰特-伯卡德博士声称，迄今为止的测试表明，这些动物并没有因为这个过程而以任何其他方式被削弱。“这次编辑将做的主要事情是有利于动物福利，因为动物不会患上毁灭性疾病。”

However, critics have argued that the creature's welfare will actually suffer because of this. Helen Browning of the Soil Association believes this only addresses the symptom of the problem and not the root cause. "It is not encouraging companies to change the way they keep their pigs so they don't become diseased in the first place", she says.

然而，批评人士认为，这种生物的福利实际上会因此受到影响。土壤协会的海伦布朗宁认为，这只能解决问题的症状，而不是根本原因。她说：“这并不是在鼓励公司改变养猪的方式，以免它们一开始就生病。”

Regardless, this is an experiment and while the technique appears to work, it is several years away from regulation and implementation. “On top of that, only if these studies are successful and the public are accepting, would we integrate these gene edits into commercial breeding stocks," Dr Tait-Burkard told the BBC.  So it seems we may have a while yet.

无论如何，这是一个实验，虽然该技术似乎有效，但距离监管和实施还有几年的时间。“最重要的是，只有当这些研究成功并且公众接受时，我们才会将这些基因编辑整合到商业育种中，”Tait-Burkard 博士告诉 BBC。所以看来我们可能还有一段时间。

词汇表

genetically-modified 转基因的

organism 生物体
genetic sequence 基因序列
hardy 强壮的
resistance to disease 抗病
nutrient 营养物，养分
trial 试验
stem cell 干细胞
genome 染色体组，基因组
drug 药物
immune 有免疫力的
DNA 脱氧核糖核酸
contract a virus 感染一种病毒
reproductive 繁殖
respiratory 呼吸的
syndrome 综合症
expose to (a virus) 感染（一种病毒）
pass on 传下去，遗传给...
symptom 症状