Question

    Scientists say they have used the gene-editing tool CRISPR to repair a person’s eyesight for the first time. The CRISPR tool makes it possible to change DNA to add needed genes or take some away if they lead to problems.

A patient recently had the procedure done for an inherited form of blindness. The operation took place at Oregon Health and Science University in Portland. “We literally have the potential to treat people who are essentially blind and make them see,” said Charles Albright. He is chief scientific officer at Editas Medicine in Cambridge, Massachusetts. Editas is one of the companies developing the treatment. Albright added, “We think it could open up a whole new set of medicines to go in and change your DNA.”

The people taking part in the study have a genetic condition that keeps the body from making a protein needed to turn light into signals to the brain, which leads to sight.

Scientists have found it difficult to treat the condition with usual gene therapy. So, they are aiming to edit or remove the mutation（突变）by making two cuts on either side of it. The hope is that the ends of DNA will reconnect and make the gene work as it should. Through a tube the width of a human hair, doctors put three drops of fluid containing the gene editing machinery just under the retina（视网膜）, which is the lining at the back of the eye that contains the light-sensing cells. Doctors believe they need to fix one-tenth to one-third of the cells to repair vision. In animal tests, scientists were able to correct half of the cells with the treatment, Albright said.

Some independent experts were hopeful about the new study. Dr. Kiran Musunuru is a gene-editing expert at the University of Pennsylvania. He said the treatment seems likely to work, based on tests in mice and monkeys. The gene editing tool stays in the eye and does not travel to other parts of the body. So, “If something goes wrong, the chance of harm is very small.” Musunuru said. “It makes for a good first step for doing gene editing in the body.”

1.Who can most possibly benefit from this new treatment?

A.Patients who are essentially color-blinded.

B.Patients who turn blind due to accidents or diseases.

C.Patients who are born with no ability to see.

D.Patients who lose their vision at a young age.

2.Which is Paragraph 4 mainly about?

A.The result of the treatment.

B.The theory of the treatment.

C.The difficulty of the treatment.

D.The disadvantage of traditional treatment.

3.What is likely to be discussed after the last paragraph?

A.The function of the gene-editing tool.

B.The limitation of the gene-editing tool.

C.The effect of the treatment on animals.

D.The research of the treatment on humans.

Answer

1.C

2.B

3.D

【解析】

这是一篇说明文。讲述了科学家发现了一种叫作CRISPR的基因编辑工具，可以通过改变DNA来治疗眼睛近视等疾病，这种工具的效果还在实验证实中。

1.

细节理解题。根据第一段“The CRISPR tool makes it possible to change DNA to add needed genes or take some away if they lead to problems. ”可知，这种工具是通过DNA的添加和去除来治疗，所以治疗的是先天疾病，且第二段中“A patient recently had the procedure done for an inherited form of blindness.”提到这个被治疗的病人的眼盲是遗传的，故选C。

2.

主旨大意题。根据“Scientists have found it difficult to treat the condition with usual gene therapy. So, they are aiming to edit or remove the mutation（突变）by making two cuts on either side of it.”可知，科学家们发现普通的理论行不通，所以他们研究出了新的理论（在突变基因的一边剪开），后文是在讲该理论的作用机制和效果，所以第四段主要是讲该治疗的理论，故选B。

3.

推理判断题。根据“He said the treatment seems likely to work, based on tests in mice and monkeys.”可知，最后一段提到的实验进程是基于老鼠和猴子身上的实验，所以接下来要讲的是在人身上的实验，故选D。