Scientist create gene-edited pigs
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
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）
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.
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.
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.
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."
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.
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.
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