問題詳情

請依下文回答第 29 題至第 32 題        Kill the mosquito and you kill the disease. That is the usual approach to controlling malaria. And if doneproperly, it works. The problem is that the insecticides employed to do the killing destroy lots of other things aswell. An old dream of those who seek to eliminate malaria is thus a way of selectively killing only what transmitsthe parasite: mosquitoes of the genus Anopheles, most notably Anopheles gambiae. And that, more or less, is whatis proposed by Nikolai Windbichler and Andrea Crisanti of Imperial College, London, in a paper in NatureCommunications. They think they have worked out how to stop A. gambiae females being created in the firstplace. That would break the chain of transmission in two ways: immediately, because it is only females that drinkblood and so pass the parasite on; and in the longer term because without females a population cannot reproduce.        The researchers’ trick is to engineer into the mosquitoes a gene for a protein called a homing endonuclease.These genes are peculiar, and are probably a type of genetic parasite. They cut particular sequences of DNA in away that damages the chromosome such DNA is found in. In extreme cases, that destroys the chromosome. (Inless extreme cases, the process of repair often copies the endonuclease gene into the repair site; hence the name“homing,” and also the suspicion of parasitism.)        Dr. Windbichler and Dr. Crisanti have found a homing endonuclease in a species of slime mould that, by astrange coincidence, cuts a sequence of DNA found repeatedly in the X chromosome of Anopheles gambiae,destroying the chromosome completely. 
29 How did Dr. Windbichler and Dr. Crisanti stop A. gambiae females being created (reproduced)?
(A)They used insecticides.
(B)They eliminated malaria.
(C)They made A. gambiae males incapable of reproduction.
(D)They inserted a gene to destroy the X chromosome of A. gambiae.

參考答案

答案：D
難度：適中0.675676
統計：A(5),B(5),C(14),D(50),E(0)

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