NT_018

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綜合寫作

Dengue is a serious viral disease that is typically spread by a mosquito called Aedes aegypti. The spread of dengue could be controlled by reducing Aedes aegypti populations. A biotechnology company has devised a way to achieve that: it has created a genetically modified (GM) Aedes aegypti mosquito. When the GM mosquitoes reproduce with wild mosquitoes, the mosquitoes in the next generation are defective and cannot survive. Releasing the GM mosquitoes to the wild would therefore reduce the population of Aedes aegypti and limit the spread of dengue. However, there are critics who believe that the plan to release the GM mosquitoes is potentially very dangerous and should not be put into practice.

Other Mosquitoes May Increase

First, the Aedes aegypti mosquito is not the only mosquito that can spread dengue. Other, rarer mosquito species carry even more powerful denque virus. The critics suggest that if the Aedes aegypti population is reduced, populations of other mosquitoes could increase to take their place and then would spread more dangerous forms of the virus.

GM Mosquito Bite Could Be Dangerous

Second, the critics are concerned about what might happen when the GM mosquitoes bite people. The mosquitoes are genetically engineered to produce a defective proteinthat is why their offspring die.If the defective proteins are passed to people when the GM mosquitoes bite them,we do not know what the effects might be

Unforeseen Ecological Effects

Third, there are concerns that introducing any genetically modified organism into an ecosystem might have unforeseen negative consequences. There are examples of this: the population of one type of butterfly was reduced by half after GM crops were introducedin areas where it lives.Introducing GM mosquitoes might have unforeseen ecological effects as well.

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